Check the "New Mystery Shopper" area, especially start with the 'Nuts and Bolts' thread to get a basic notion of how it works. And yes, there really is mystery shopping and yes, it really works. You won't get rich doing it. You won't be getting 'free laptop' or 'free $500 gift card' or any of the scammy stuff that is email come ons. But as supplemental income and some useful reimbursements it can work quite nicely.