I remember in the past the pre-authorization charge was only $1.00, how do i know? Lets just say I have had to make turn-around trips from Northern California to Southern California  and would use a pre-paid credit card with $10 on it and was able to get gas multiple tims there and back. Do i still have the pre-paid card in good standing.. YES! 

Here are some notesI have found on the internet regarding this.

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 Many places that take credit cards do a pre-auth, to see if the card is good. For example. You go to a gas station to put $20 in your tank. You have $60 in your checking account. That station does a $90 "pre-auth" when you swipe your card. Which means that unlike a credit card, that $90 has now been removed from your account.

On a credit card, it doesn't affect your immediate balance, and on a $90 pre-auth with a $60 balance, your card will be declined. Not so with a debit card. The withdrawal is immediate. The pre-auth will eventually drop off after a week or so, but in the meantime, you've got overdraft fees. And if you don't happen to check your balance every day, you may not ever know about it until you do check it, or you get a notice from the bank

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 Using a debit or credit card to buy gas could diminish your bank account more than you realize.

Stanley Allen knew gas was expensive, but when he recently bought $20 worth of gas with his debit card, he found out that it cost even more.

"Later on that afternoon, I got home and I checked my account, and along with the $20 worth of gas that showed, there was a $100 hold put on my account," Allen said.

The $100 was not technically gone -- it was just off limits. But what happened next was painful.

"Everything that came in after I pumped the gas bounced, so I ended up with $105 in overdraft fees," Allen said. Click to read more.