As a college student in California with it's declining economy, finding work can be rough. You'll try almost anything to make a few extra dollars here and there. One avenue is being a Secret Shopper or Mystery Shopper. This is basically where companies reimburse you to visit businesses and rate them on their service. Secret Shopping isn't what it used to be though.
Back in the day, businesses themselves would hire shoppers to see if their employees were slacking on the job. Nowadays, you can sign up with companies like BestMark who try to match shoppers with businesses all over your area to "shop."
After signing up with BestMark, you're able to choose how far you'd like to travel to "shop." The three different options available to me within a 50 mile radius was to try out an upscale restaurant in San Diego, purchase a video game at an all gaming store, or pretend to go car shopping. The reimbursement amounts was anywhere from $5 to $25.
Nothing that's going to make you rich but it is a few extra dollars. I'd say that if you have the time to throw away, why not get a little money out of it. But for someone who is looking for real income, this is definitely not the way to go.
I haven't tried any other Secret Shopper sites out yet so nothing to compare it to, but based on BestMark, Secret Shopping is not a way to to support yourself financially.