PayPal is a nice way of paying for stuff on the net, as well as receiving payments, donations, etc., without having a credit card, but some sites require a credit card backup. They verify your bank account and make sure you are you. You add funds to your PayPal account from your bank account. It can take a few days for it to actually get into your account, so plan ahead. Waiting for your non-credit card backed payments takes time too, because PayPal actually sends an e-check to whoever you are sending the money to. Their site can be a little confusing, but worth it.
I hope this helped.