Yes I do it all the time. Be careful of scams though. Anyone who charges you to refer you to Mystery shop jobs is not legitimate. Secrecy is of utmost importance..you must not talk about what you do except in very general terms, and when you are on a job, never ever reveal yourself. You must roleplay as an ordinary shopper and do whatever your shop guidelines instruct you to do. You must have good observational skills and good written communication skills because each shop requires a report to be submitted. The report when read, must give the reader details of what transpired during the shop, as though they were watching and listening to a video of what happened from the moment you walked in until you left. Timing and descriptions of people must be reported.
Choose your shops wisely. Weigh the cost of gas to drive there against the shop fee. Mapquest can estimate your gas costs when you get driving directions. Recently I was offered a lunch shop with a $25.00 flat fee. The meal would have cost me about $35 plus the cost of gas to get there. Unless you can get a date to take you there and treat you (you pocket the $25) it's not a good idea. I have to work around my part time time job. I shop mostly on my days off, and I usually do 2 shops each day off. Sometimes if a shop is in my city or close by, I can go do it in the morning before noon ( thats when my job starts). I really apply myself, and I make $150 to $200 a month. If I wasn't restricted by my job, I could do more. I have to turn down a lot of shops. For February I have a $10 shop and two $40 shops. I shoot for a minimum of $100 a month, so I am already almost there. from just those three shops. Hope that helps!