Most sellers accept Paypal. Some will only accept Paypal, which processes your credit card payment without giving your financial information directly to the seller. Which is comforting.
It is a good idea to sign up for the service before beginning to shop, because confirming your new account takes a couple of days.
Paypal offers strong buyer protections against unhappy transactions.
Some sellers do accept credit cards directly. These are usually professional dealers and sometimes quite large businesses.
