I've seen a lot of posts recently from people who have had their credit card numbers stolen after making purchases at various e-cig dealers. While no system is absolutely foolproof, I've found about as safe of a way to protect your credit and keep criminals from stealing you blind.
This method involves PayPal. Some financial institutions may offer similar (maybe even superior) methods of fraud protection, but this works for me and probably will for you, too.
We have three checking accounts at two different banks. The one at Bank #1 is the joint account used by my wife and I to conduct our routine family affairs (mortgage, groceries, utilities, tuition, etc). Another account at Bank #2 serves as my business checking account for my consulting firm. The third is also at Bank #2, and it is a personal checking account with the balance never climbing over $50. This is the Black Hole account. It's a basic, "free" checking account with no overdraft protection and no credit line attached. Get the cheapest account they offer, with no bells and whistles whatsoever. There will be a monthly service charge in many cases, but it's worth the price for keeping cheap.
I can fund the account via any of the normal means--cash deposits, check deposits, intra-bank transfers from Account #2, electronic transfers from other banks, etc. If at any time the balance exceeds $50, the excess is swept electronically into Acct #2, the business account.
You don't have to use PayPal, but doing so does make this a lot easier when dealing with retailers who accept that form of payment. Despite what you may have heard, PayPal is at least as safe as Chase, Citi, JP Morgan, et al. When linking PayPal to an account, always link it only to the Black Hole account. Go ahead and apply for Smart Connect, which is an online revolving credit line serviced by GE Capital. The rates are usurious, so make sure you pay the balance at the end of each month. You can also apply for a PayPal MasterCard Debit Card. I have that, too.
PayPal offers you the opportunity to link your debit card to your PayPal account or your credit line. Link it to the former, not the latter, and don't link it to any of your checking or other accounts. As long as your PayPal account is also kept to a minimum balance, then if the debit card number gets compromised, all they get is what's in your PayPal account.
If you don't want to use PayPal, you can still use the Black Hole account to make online purchases, using either the debit/ATM card that comes with the account, or by linking a "smart shopping" credit card to it. Again, the key is to keep balances in the most vulnerable accounts to an absolute minimum and not using your personal credit card or primary account debit/ATM's for online shopping.
The biggest threat to this method is your own computer security regimen. Do not use the same passwords for any accounts at financial institutions. If someone compromises your PayPal account password and you're using the same password elsewhere, the crook is sure to find out. Change your passwords frequently, and use mixed case letters with numbers. Download quality malware/antivirus software such as LavaSoft's AdAware (free for personal use; solid protection systems).
Do not conduct business with your bank, PayPal or online vendors using hotel or other WiFi networks, even if they say they're secured.