Amazon will save your credit card number if you allow it, then all you have to do is set up a password to access your account whenever you want to buy something. Or, if you prefer, you can not let them store the number, in which case you have to give it every time you want to buy something. I've had a credit card account with them for years, and about the only bad thing about it is, the "Purchase With 1 Click" instruction can sometimes make it TOO easy to buy stuff, and your credit card bill can get really high before you realize what you've done.
(You can also set up a Paypal account using that same credit card, or a bank account, and the danger is about the same. It's way too easy to run up a really big bill before you realize what you've done. So, whether you get one, the other, or both, just keep track of how much you spend, so you won't go into shock when the bill does come in)
