When you pay at the pump, a pre-authorization is done for an amount between $50.00 and $75.00. This is due to the fact that the authorization is done before the amount of the transaction is known. If you do pay at the pump, the transaction will settle for the amount you actually pumped within 24-48 hours of the initial transaction. You can avoid this pre-authorization by pre-paying inside the store or paying after you pump.