So.. what's the problem? Budget isn't unique in this circumstance. Other car rentals also put a hold on your creditcard. Sixt for example sometimes takes more! But its just a creditcard hold. Its not as if they've taken your money and not giving it back to you. Your hold will be released once you complete your rental.

Just make sure you have enough credit on your cards when you rent the car. Otherwise charge your rental to a charge card...