If you are arty or crafty, the potential market for your side hustle is worldwide, not just Trade Me, your own website and word of mouth. I have bought the occasional item on ETSY.com, a worldwide craft marketplace.
Time holds people back and so does imagination. One way to open your mind to ideas is to look through jobs on Kwota.co.nz and other freelance marketplaces such as Fiverr.com.
When I looked last week there were jobs on offer with varied requirements. One needed the ability to type and understand some Te Reo.
Another was looking for someone who could edit home videos. A sofa owner wanted someone to make a loose cover to fit.
In the past to get this type of side hustle you would have had to advertise or publish a website.
That, of course, is still possible.
Plenty of people make money by buying (or scavenging) second hand items and re-selling. Property investor Rich Visick, who works part time in a scrapyard, says people often come in with old hot water tanks, for example, that fetch about $30 for the scrap metal.
Increasingly, clever Kiwis are buying in bulk direct from China and re-selling on Trade Me. One sells reusable shopping bags for $4.50 plus postage. The very same bags can be bought via Alibaba.com for as little as US20c each. It's not going to turn the seller into a millionaire overnight, but the money from this type of wheeling and dealing does roll in especially if you find a market for more than one product.
Upcycling is a big thing. The upcyclers buy cheap old furniture, for example, or retro blankets, turn their second hand raw materials into something trendy and make several hundred per cent profit for the work.
Search the word "upcycled" on Trade Me or ETSY for ideas. It's not just furniture. Sellers on Trade Me upcycle all sorts of things — one turns old coffee sacks into reusable bags and sells them.
Ask around most offices and you'll soon find colleagues with other little businesses. At one insurance company I know, a member of staff bakes cakes at night.
It's a bustling business with colleagues buying the baking for work and personal celebrations.
This shows that not every skilled job requires a three-year apprenticeship.
Short courses can give you new skills and you can use them to teach others anything from swimming to quilting.
Joining the "sharing economy" and supplementing income that way works for some.
I have mixed feelings about the rapacious multinationals that offer "gigs" and the power they hold over the little man's income.
Having said that, as a side hustle, the sharing economy is sometimes a source of money that wouldn't otherwise be available to the person.
I read a great story about a car owner who uses Uber to pick up fares as he drives to and from work, paying for his daily commute.
And plenty of empty nesters are making money letting their children's former bedrooms or sleepouts to tourists.
Finally, beware you don't fall into the trap of using extra money to buy more because you think you deserve it.
The other big fail is what's called mental accounting — where you assign money to different categories in your head according to how it's obtained.
Side hustle money is excluded from your budget and seen as a windfall.
If you're in debt or haven't saved enough for your house deposit, retirement, or business start-up fund, this is an expensive mistake.