I use paypal when I buy from e-bay. So, I had a paypal account before I started mystery shopping. Paypal's website is not always user friendly. Very often I have to call their customer service to get through my objectives.
As mentioned, you do have to have a personal bank account registered with them. When you give them your banking information, they will send two small payments to that bank. You will then have to let paypal know that it was received and submit the two small amounts according to the instructions they give you. Then you are set to go.
When the mystery shop submit payments to paypal, you can then transfer that payment to your personal bank account.
Very often, I find that the mystery shops lump payments instead of listing which shop your payment is for. This makes it hard, because then you have to go into their websites to find out.
If you are working for multiple company's, this is a pain. You will have to keep good records of all of your jobs.
Rlly