I've thought about doing Mystery Shopping several times. My thing is, I have to spend my money before I get paid! What if the money don't come thru? Legitimate mystery shopping opportunities are out there, but so are plenty of scams. If an opportunity is on the up and up, you won't have to pay an application fee or deposit a check and wire money on to someone else.
If a company asks you to pay a fee to apply, run. Mystery shopping companies will not charge you to complete an application. The companies that want to charge you may not always be scams, but they are not mystery shopping companies. Mystery shopping is a very real thing that people actually get paid money to do.
If you receive a letter and a big fat check for mystery shopping, do not take it to the bank. The only legitimate secret shopper assignments pay $5-10 each assignment. If you love to shop and know what great customer service looks like, then become a Mystery Shoppers and help make your local businesses better!