Zach here from Abine (we make the Masked Cards). If you use our browser extension you can make disposable credit cards for your transactions right from online checkout pages. The best way to use a Masked Card is to create it for the exact amount of the transaction once you know the total. Then when you use it, the card instantly becomes worthless. In this way it works like a gift card.

We also have iPhone and Android app's where you can create these Masked Cards in stores as you're about to check out. Cashiers just need to be willing to type in the 16 digit # and expiration, which they usually are fine with.