Satisfaction Services ( http://www.satisfactionservicesinc.com/ ) is a mystery shopping company, my favorite one in fact.
Once you’re registered with them you can accept assignments to go shop at certain stores they have partnered with, they will expect you to write a detailed report afterwards telling the areas of the store you shopped, the employees you talked to, what they said, how they acted, etc.
I personally bring a voice recorder and leave it in my pocket so I don’t have to remember things, I just play it back and type up the report later at home.
Typically you’ll be assigned to shop certain areas, you’ll need to buy something from the assigned area, they’ll reimburse you for your purchase (typically up to about $30) and pay you also (typically about $10).
There are some scammy mystery shopping companies out there, which is why I am reviewing these for you, I hope it helps. Satisfaction Services and ACE are two that I have a lot of experience working with and can personally guarantee that they are good companies.