There are several marketing companies that use this trick to get people into paying for something that might come as an unbelievable shopping experience.

You are promised a $500 grocery coupon if you participate in a so-called survey and enroll into 3 or 5 companies that will spam you for ever after (let’s say one deals with cosmetics, one with travel, one with food). To enroll, you have to pay about $10 or $20 to each of these companies, but you think this is fine since you are getting $500 back – it seems a good deal.

Then you wait for the coupon, which comes in the mail as either a brochure or a card with a balance, perfectly legitimate since it is, as promised for a total of $500.

The problem is that the $500 value is distributed in over 1,000 different ways: $1 off pet food, $0.50 off frozen food, $1 off magazines, $0.50 plants, etc. The full discount – that you still pay for - would be worth full $500 only if you buy products from every single section of the store.

How to avoid: there’s no such thing as a free lunch – no grocery store is going to start dishing out $500 of free food to its customers.