How is it legal for gas stations to overcharge me for my gas just because I used a debit card?

If I pump $25 worth of gas, and the station holds $100 to ensure that they get paid, its perfectly fine with me. However, I don't understand how they can charge me all sorts of extra fees and end up keeping $45 of the $100 when I only bought $25 worth of gas. I've been searching the internet and theres all sorts of complaints, but no where can I find the IRS coding or constitutional backing that makes this legal!

The gas station shouldn't charge you anything over the amount you actually paid for the gas.

Have you asked your bank about this? Are you sure it's not some sort of bank fee you're being charged?

Not trying to be a smarty, but if you gave them an OK to withold the $100., you're nuts and dealing with the wrong people, plus the extra fee of $20, is illegal.
Now, if the station has a sign posted that the price shown reflects a "cash sale price" then they can add sometimes 2 to 3% to recover the charge applied to them from the credit card company, but no way the sour deal you just got.
Call the authorities and file charges.
When you use a debit card, there should be no extra charges s they get the money in their account as soon as the card is read and entered into the computer

I have read through the merchant agreements, and according to the contract the seller signed with the credit card/ debit card processors, they are NOT allowed to charge fees (known as "surcharges") for customers using dr / cr cards instead of cash.

You should be able to contact your bank and dispute the charges.

get a police report and take them to court.
http://search.yahoo.com/search?p=free+le…

Send your reciept to your bank showing that the charge was only $25.

Dude that is totally bogus. I would contact a lawyer