I'm confused about what you're saying. Are you prepaying to the credit card for a charge that hasn't been posted to the account yet? I can understand that it is one way to set aside money for an expected charge to come, but that is not the best practice for online purchases. I've ordered things from Amazon that became backordered and subsequently canceled because the item became unavailable. You can come up with other ways that you can set aside money for impending charges.