If you are just getting started as a shopper, I would recommend Market Force, Stericycle, IPSOS and Maritz. These companies deal with a lot of new shoppers so generally offer clear instructions. They also offer shops everywhere in the US. If you already are doing shopping, there is an Official List of Mystery Shopping Companies at the bottom of each page which has links to conversations about the companies as well as links for registration. Some California shoppers may provide you with names of companies they know about in your area, but generally since this is a small business the expectation that each of us explores for opportunities on our own.
One general source for information is the free version of Jobslinger.com that will show you jobs in your area. You will find that most of those jobs have been taken already, but it is a source for information of companies who have clients in your area.
I am on the other side of the country so could guess at a few companies, but I suspect Jobslinger would be of much more assistance to you.
Edited 1 time(s). Last edit at 08/09/2015 08:13PM by Flash.