This is probably going to get closed as it is not the type of question for stackoverflow. However, people can make payments via PayPal without an account there. They would have to enter payment information. You can probably get some of the data needed for this from the Facebook data, such as email address and name. But you aren't going to be able to have them log into PayPal or other via Facebook.
Another option would be to look into the Facebook payment system. https://developers.facebook.com/docs/payments/