We often say the safest way to make purchases on the Internet is with a credit card, because federal law protects credit transactions from fraud. That law does not protect you using your debit card, PayPal, money orders, wire transfer, etc.

You can take this one step further by asking your credit card company for a single-use credit card number. It's also called a virtual number. This a temporary number (assigned to your account) that's good for a limited number of purchases - maybe one or a few more - and after that, it's invalid. Thus, if that number gets into a thief's hands, it won't do him any good.

This article from bankrate.com explains things further, including some cases where you don't want to use this type of account number.