mystery shopping - its not a con its true.
all you need to do is fill in a few forms reporting on the service and so on, you get all your expences ie the cost of your mcds and pertol / bus / train fares etc, Plus you will get paid a small amount per job.
My mum runs a compnay that does this for loads of companies, asda, currys, halifax loads of big compnaies have contracts with her firm to make sure that their employees are doing their job correctly.