Payments with Paypal
Paypal is an online bank basically. How it works is you have your account balance of zero dollars when you create an account.
If you sell an item on eBay and the buyer pays you thru Paypal you now have more money in your paypal account that you can use just like cash but it is online.
Another way to add funds to your Paypal account is to add a credit card or check number to your Paypal account. Then you can add funds from there onto your Paypal account and then pay people with you Paypal funds. That way you will not have to give them your credit card number or check number