Sometimes the freebie is only insights. The salesperson or scammer makes out that they're sharing secrets with you or valuable information that they've spent years learning. You feel indebted to this kind person.
There are other common ways of making this pitch work. Someone wants you to spend money with them - as a genuine purchase or a scam. They ask for a high sum - say $3000 - to begin with. You baulk. They then go away and come back and say just for you the boss has allowed a special price of $2000. How would you like to pay? They've done you a favour by reducing the price especially for you and now it's your responsibility to sign up.
The concept of scarcity is very commonly used as a persuasion technique. Whatever it is that is being sold is made out to be unique and the victim is made aware of what they'll "lose" if they fail to take up the offer.
Time pressure is usually coupled with the scarcity. Buy within the next hour and get free steak knives is standard patter, says Lee Chisholm, operations manager at NetSafe.
During the last property boom I went to an apartment sales seminar run by an otherwise reputable real estate agency where, surprise surprise, the apartments were allegedly selling so fast you'd have to sign up that night or miss out.
Telephony and power salespeople who appear on my doorstep regularly use the same tactic. Like the apartment salespeople who stick the information to the wall and won't let you take the details away, the door-to-door salespeople are only in my area today and if I don't sign on the bottom line I won't get this alleged deal-of-the-decade they're offering.
Romance scams are a classic for using the speed technique. The scammers move fast when they find a prospect, says Chisholm. A lonely Kiwi single who is desperate for love is showered with compliments and poems over hours or days.
"They say: 'I will do anything for you, even if it means coming to New Zealand. But I just need some money first'," says Chisholm. Sometimes the victims send their transcripts to NetSafe. So similar are the victim's stories that Chisholm wonders if the scammers share notes.
A classic scarcity story is the flatting scam that has sucked in many Kiwis desperate to get a decent rental. They may reply to an advert for a too-good-to-be-true apartment on the waterfront for a really cheap weekly rental cost. It's all done over email because the "owner" is overseas "working in an orphanage" or something designed to pull your heartstrings. "They say: 'You can't look at it because I am not there. Once you pay the bond and rent I will send you the key'," says Chisholm.
We are very easily persuaded by fake authority. Salespeople and scammers alike make a big effort to sell themselves as knowledgeable, knowing that we'll value them more for it.
One of the tricks is to have someone else introducing them. It doesn't matter if the person is connected to the salesperson/scammer. I saw this recently where the sidekick of an "entrepreneur" running a seminar warmed the audience up by gushing about how lucky they were to have her boss's time.
Another way of doing this is for a cold caller to arrange a meeting with you and their "expert".
This also works for scammers who tell us they're from the Inland Revenue Department, bank or other organisation.
The next ploy is to ask you to commit to something. It's probably a small sum of money at the beginning. But you're asked to make bigger and bigger commitments. In a recent scam dubbed "puppygate", Kiwis were offered pedigree puppies from overseas. Once they'd paid a shipping fee they were committed to the purchase. Next came a request for insurance, and then a customs fee. The puppy, of course, was fictitious.
Another weapon in the salesperson's arsenal is to find common ground. We all like to say "yes" to people we like. So the salesperson pays us compliments and pretends that we're co-operating.
He or she may find things out about you - such as your child plays rugby - and then purport to have this same interest in common.
Salespeople of the legitimate and illegitimate kind play on fear. The classic example of this, says Chisholm, is the vacuum cleaner salesperson who comes around, does a demonstration and says: "Oh my God, look at the mites in this carpet. Do you have children? You have to DO something about this." The customer (or victim as some people would prefer to call them) is scared into making a purchase.
It's the same with those "germy germs under the rim" that we heard about on TV for years scaring us into buying XYZ brand of toilet cleaner.
The baby equipment industry is great at using this persuasion tactic to wrest unnecessary money from new parents. "If you don't buy this 2014 model, or this new-fangled highly expensive model you're risking the life of your baby."
A recent scam that has used fear involved new immigrants to New Zealand being cold-called and told that there was a mistake with their visa and they would be deported the next day if they didn't pay $900 by Western Union that day.
Greed is an easy emotion to play on. We think our life would be so much better if we just had a little more money, says Chisholm.
NetSafe had a complaint last month from someone who had borrowed and lost $660 to a Facebook scammer. The scammer had hijacked a friend's page and was chatting online with the victim about having just won $50,000. The victim was convinced his name was on the list of winners as well and was directed to a phishing page that looked genuine but was not. To pick up his $50,000 the victim had to pay $660, which he borrowed, in administration charges.
Then there's consensus. We look to the actions and behaviours of others to determine our own. We hear that three people in this street have bought this broom already. If the neighbours had then it must be a good buy, mustn't it.
The investment scammers go one step further and tell you how other Kiwis have made millions doing whatever it is they're selling by getting in early. You're not going to want to miss out are you?
Last year 562 people told NetSafe they'd lost money to scammers. Those amounts ranged from $3 to $224,000. The highest figure was for a dating scam.
Collectively New Zealanders spent millions of dollars on things that were sold to us using the same persuasion techniques.
Watch and listen next time someone tries to sell you something. What persuasion tactics are they using?
Being aware is the best defence.