Confero, Strategic Reflections.
***CAVEAT*** Not all areas have grocery shops with the same MSC. What's available in my area with, say, Confero, may not be available in your area. Just sign up with as many MSCs as you can, perhaps 5 each day. At the bottom of each page of this Forum is a link to the Official List of Mystery Shopping Companies. That's a great place to start. Then do your due diligence by reading on this Forum about the general consensus of whatever MSC you are contemplating working with. Some have great reputations, some OK, and some rotten! So just do your homework, and have fun and good luck!