One of the first questions people ask me is where do mystery shoppers go? Who do they shop? When you sign-up to shop you will start to see the offers come in. Due to confidentiality rules, I can't tell you the exact names of companies. I will reveal some of the industries that I have shopped. You can find what are you enjoy shopping the most. Most shoppers I know have a favorite type of shop they like to complete. Here are some of the places that are mystery shopped.
Restaurants(Fast food to fine dining)
Car test drives
New Home Sales
Sign-up with lots of companies, start completing shops, and start trying various industries! Post a comment for what your favorite type of shop is to complete!