Citi credit cards (and maybe others) have a good feature where you can set a "virtual card number" with a specific credit limit and/or expiration date. Great wa

Citi credit cards (and maybe others) have a good feature where you can set a "virtual card number" with a specific credit limit and/or expiration date. Great way to ensure that your card can be charged once, then payment is denied when a company tries to auto-renew you.