Here, Femail tots up what she has managed to spend so far ...
No cattle class for Pippa - The flights
As a wealthy hedge fund manager, with plenty of family money behind him to boot, travelling cattle class with his new bride is out of the question for James Matthews.
But if they did travel first class, surely even he would have blanched when handing over his credit card to cover the website price of £12,906.27 ($23,292) each - that's £25,812.54 ($46,585) - for return tickets on a British Airways flight from Heathrow to Los Angeles.
That would only cover the first leg of their trip: the best seats available - business class - from Los Angeles to the island of Tahiti (in order to get to private resort The Brando, on the French Polynesian atoll of Tetiaroa) could have set them back a further £3,276 ($5,912) each; £6,552 ($11,825) in total.
After their stay at The Brando, the happy couple were off again, to Sydney, via New Zealand.
The cost of two business-class seats with Air New Zealand would have been a relative snip at the advertised price of £2,862 ($5,165) for two.
Come Thursday, it was time to head to the Northern Territory - two one-way business-class tickets to Darwin would have cost £2,670 ($4,818) in total - en route to one of the world's last great wildernesses, The Kimberley, or Ayers Rock.
Even in the unlikely event of this turning out to be their final port of call before heading home, they will still need further flights to get them from Darwin back to Los Angeles, which could easily be another £6,500 ($11,731).
COST: £44,396.54 ($80,125).
Raw kangaroo - The food and drink
All food and drink was covered in the £5,000-a-night ($9,023) cost of their villa at The Brando. But it was far from an all-you-can-eat buffet at double Michelin-starred Parisian chef Guy Martin's sophisticated on-site French restaurant.
When they fancied something with more of a kick, there was also a choice of top-notch East-West fusion food at Bob's Bar, plus cocktails galore, many of them said to be named after the resort's A-list guests.
Then, arriving late on their first night in Australia, the pair are thought to have opted for dinner at their hotel, where the tasting menu - a favourite of Pippa's - included slow-cooked wagyu beef cheek and Tasmanian salmon, with matching wines. That was a relative bargain, at £84 ($151) a head.
On Wednesday they ventured out to some of Sydney's most renowned restaurants. Lunch at Cottage Point Inn, on Wednesday, meant a starter of kangaroo tartare for Pippa and duck for James, followed by the degustation menu, a seven-course selection of mini-dishes, including roasted quail and smoked eel, for £80 ($144) a head, plus £43 ($77) each for paired wines, making a grand total of £246 ($443). Dinner on Wednesday was at the Flying Fish, where main meals cost up to £100 ($180). Specials that night included oysters, crab and octopus.
With starters, desserts - there was passionfruit soufflé, ricotta cheesecake and coffee praline to choose from on the night - and a decent bottle of wine, that could easily have been another £300 ($541) out of the coffers.
COST: £714 ($1,288).
£400 ($721) for sunset walk
Every pastime that took the couple's fancy - from snorkelling to paddle-boarding, canoeing and kayaking to deep-sea fishing, tennis, cycling and fitness classes - was part of the package during their stay at The Brando, on the French Polynesian island of Tetiaroa.
In Oz, however, the honeymooners soon racked up a big bill. Sticking to their strict pre-wedding fitness regimen, they kicked off their first full day with an early morning jog around the harbour, accompanied by a man who is thought to be a personal trainer. The most sought-after of these charge more than £150 ($270) an hour.
Rather than paying £2 ($3) for a local bus to take them to Rose Bay, a popular harbourside location in the eastern suburbs, later on Wednesday, they opted for a water taxi, giving them a private romantic cruise from Circular Quay at a cost of £172 ($310).
When it was time to head back for lunch, the newlyweds did it in real style, hiring a seaplane for a bird's-eye view of the city's beaches, including Bondi, and magnificent architecture. It cost £473 ($853) for a 15-minute flight.
Afterwards, they bravely conquered the Sydney Harbour Bridge Climb. Wearing matching overalls, Pippa and James strode across the 134-metre-high bridge, giving them a unique view of the city, including the Opera House and six lanes of rush-hour traffic below them.
Visiting at peak time, when the sun was setting, would have cost them £411 ($741), according to advertised prices.
£1,000 ($1,804) on swimwear - The wardrobe
Pippa hasn't disappointed fashion lovers this past week, modelling an eye-catching array of expensive dresses and bikinis.
While there was little call for anything except swimwear in the 75-degree heat during their week at The Brando, Pippa will have fitted in perfectly, thanks to her love of Melissa Odabash bikinis, which retail at £190 ($342) a set.
She was also photographed in a Biondi Antibes under-wire bandeau bikini, which cost £115 ($207), in white, to show off her tanned and toned physique.
Another day saw her photographed on a paddleboard wearing what appeared to be a Heidi Klein two-piece in blue, which retails at £190 ($342).
Assuming she isn't doing too much laundry on holiday, and has worn at least three different bikinis, that's £495 ($893) on swimwear - more than the £400 ($721) the average woman spends on her entire honeymoon wardrobe.
Once the couple were in Sydney, Pippa gave several pieces by her favourite designer of the moment, Kate Spade, an outing, including a blue and white print dress (£335) ($604), teamed with Castaner wedge lace-up espadrilles (£58) ($104), perfect for a stroll along the sand in cooler climes.
That evening she wore another Kate Spade, a red and pink tile-print dress (£318) ($573) with LK Bennett sandals (£70) ($126).
And for a ride in a water taxi, she chose a black and white Talita dress (£464) ($837), again with her favourite espadrilles.
For the flight to Darwin, Pippa sported a rather regal broderie anglaise Orla Kiely blouse (£210) ($379) with jeans and espadrilles.
Meanwhile, long-limbed James lazed around The Brando in Vilebrequin swim shorts, which cost £165 ($297) a pair - for three pairs, that's £495 ($893).
His city-break wardrobe appeared to consist of Church's shoes (approximately £380) ($685), Emmett shirts (about £145 ($261) each, so that's £1,015 ($1,831) for seven) and Oliver Spencer chinos (about £170 ($306) a pair, making £510 ($920) for three pairs).
COST: £4,350 ($7,850)
Designer luggage - The accessories
Every smart woman knows that when you're on holiday, you need to pack accessories that work for both day and night.
Pippa, an adept traveller, has managed this to perfection. Her chain-strapped black Aspinal Lottie handbag (£425) ($767), crafted from Italian calf leather, made its first public appearance early on Wednesday in Sydney, as did her Italian retro sunglasses by Persol (£192) ($346), a brand that has had iconic status since acting legend Steve McQueen sported them.
Both also served as the perfect accompaniments to her evening attire for the couple's posh dinner at the Flying Fish.
Jetting to Darwin on Thursday, Pippa opted for more spacious and practical hand luggage - the Sensi Studio straw tote bag, again topped off with her Persol specs.
Given that the tote was handcrafted in the Andes and took three days to make, it could be considered a bargain at £150 ($270).
To keep track of time in the most stylish way, Pippa also wore a Rolex Oyster Perpetual watch with a mother-of-pearl dial, estimated to be worth £8,000 ($14,438).
Throughout, of course, her engagement ring, a huge diamond circled by a cluster of smaller diamonds and valued at about £200,000 ($360,959), twinkled in the sunlight.
COST: £8,767 ($15,822) (engagement ring extra)
Dogs on a jet - The Scottish leg
The Matthewses are expected to round off their no-expense-spared honeymoon with a visit to one of James's family homes in the Scottish Highlands - which, thankfully, will only cost them the price of a flight.
However, a source says it is almost certain they will fly by private jet to Inverness - which, assuming they fly from London, would cost around £4,000 ($7,219) - accompanied by their beloved dogs, which they are said to have missed while Down Under.
From there, they will embark on the 45-minute drive to the Glen Affric Estate, which is 14 miles from Loch Ness.
As the eldest Matthews son, James will one day inherit the title from his father David, who also owns a hotel on the Caribbean island of Saint Barthelemy, and become laird of the 10,000-acre estate.
Pippa would then be able to use the courtesy title of Lady Glen Affric.
Glen Affric's eight-bedroom luxury lodge comes complete with chefs serving locally sourced meat and fish, and a full team of staff to meet a presumably exhausted Pippa's every whim.
After all, so much travelling is sure to tire a girl out. Isn't it?
COST: £4,000 ($7,219)
But at least they got a discount on their private South Pacific beach!
With money clearly no object, where better to whisk a bride than to the French Polynesian atoll of Tetiaroa, in the Pacific Ocean, once owned by the late film star Marlon Brando?
The Brando luxury eco resort, where Barack Obama was recently a guest, has 35 thatched villas, each with its own pool and beach, giving the newlyweds the illusion of being marooned on their own private desert island - albeit with attentive staff to meet their every need.
Although it was just the two of them, to dispel any possible cramped feeling, the couple are understood to have rented a three-bedroom thatched villa. Pippa needed somewhere to put all her bikinis, after all.
For this, a source says they paid a discounted rate of £5,000 ($9,023) a night - the standard fee, according to the website, is almost £8,000 ($14,438) - making a total of £35,000 ($63,167) for the week, from May 23 to 29.
As it was all-inclusive, with cocktails available at all times, at least they didn't have to worry about exorbitant restaurant and bar bills when they checked out.
Besides a steady flow of gourmet food and drink, the couple enjoyed views of a crystal-clear lagoon from the master bedroom on the top floor of their villa.
They could even share a sumptuous outdoor bathtub and take in the spectacular scenery around the atoll, which lies 30 miles north of Tahiti.
Add to this a pool with decking, linked to a private white-sand beach, and you can see why The Brando was the perfect escape from prying eyes - and camera lenses.
Leaving it behind must have been a wrench. But thankfully it wasn't too much of a come-down for Pippa and James, who spent Tuesday and Wednesday night this week at the Park Hyatt hotel in Sydney, right on the rocks beside the city's Opera House.
The penthouse suite they are rumoured to have stayed in - complete with round-the-clock butler service, a marble bath and magnificent view of the skyline - could have set them back £11,000 ($19,852) a night, making the cost £22,000 ($39,705), just for this short leg of the trip.
The couple then flew from Sydney to Darwin, in Australia's Northern Territory, on Thursday and are believed to have flown from there to either Uluru - also known as Ayers Rock - or the wilds of The Kimberley in the west, an area of dramatic gorges and unspoilt coastline.
Where, it's pretty safe to assume, the couple won't be slumming it.
