Welcome to the Forum.
I have been Mystery Shopping for about a year and a half now. Yes you can make money doing this! How much depends on how much time and energy you put into growing your business. And yes this is a business. (I am finally thinking that way myself --- Only took me over a year!)
Good luck with your endeavors. Check out the "stickies" in the New Mystery Shoppers section. They will teach you everything you ever wanted to learn about this Business, plus some.
Lady Marius
Canadian Mystery Shopper