I work with 3 different companies. They aren't all scams, and some pay cash. However, it takes 6-8 weeks to get paid. So, if you're looking for holiday cash, this isn't a good option.
Additionally, many companies suspend mystery shopping during the holiday season anyway.
A few companies I like are Beyond Hello and iSecretShop.
GfK is legit but your chances of getting work before Xmas as a new shopper are slim. Plus you spend your own money on shops and don't get reimbursed for 30-60 days after you submit receipts. For services like manicures, meals, etc you don't get paid. You just get reimbursed up to a certain amount
The chances of their getting you to cash a counterfeit check is so high it's not worth bothering.
Perhaps a market research company with local offices that you could visit first hand would be safe enough.
Most don't really pay anything, you just get food or discounts on products you probably do not need.
None
most are.. so leave them alone
