Do they rent to 21 year olds? Whats the surcharges and do they accept debit cards?

The tax-rate is high as it gets. Whatever your rate, double that number to cover the taxes. Love field is much less expensive. Yes, they will rent you at 21, however you need a credit card, not a debt. Some agencies will take a debt card from a reputable bank, but only if you have your plane ticket with return flight date.

Not sure on that. But the facility have most of the national rental car counters. It should work the same way as its outside this airport. Call to Avis/ Budget customer care and ask.

Yes, I was charged 150 dollars for three days of rent, I do not remember exactly how much additional it was per day for being under 25 years, and withholding on the credit card is 200 dollars that they return to you at the end of the rent

I know that some rental car companies do rent to drivers under 25. However, those I have seen that do will charge an additional charge if under 25. I'm not sure of the amount though...

Each rental car company has its own rules and pricing structure. Please contact the different rental car companies to find the best deal.

Most agencies will, but there will usually be a $200+ fee In addition to normal rental fees.