But before you sign your rental car contract, you'll want to know these tips from Edmunds.com.
And if the reservations don't require a credit card in advance, you can make more than one and see who'll offer you the best deal at pickup.
Next, reserve the smallest car you can.
And if the rental agent offers you an upgrade, don't take it unless it's free.
"Chances are, they're offering you an upgrade either to make an extra couple of dollars a day or because they don't have the car you reserved on the lot," explains Jeannine Fallon of Edmunds.com "They want to get you to pay for something they would otherwise have to give you for free."
Chances are you can also turn down the insurance that the rental company offers.
"If you have car insurance and you have a credit card, you probably don't ned any of the insurance that a rental car company is going to offer you," Fallon says. "Read the small print, call your credit card company, call your car insurance company and find out. Chances are you're going to be able to save that and sometimes, it's 50% of the car bill."
Also, don't select the pre-paid gas option. The per-gallon price is usually much more than you would pay filling up at a gas station.
And finally, check the car thoroughly for damage, and make sure that damage is noted on your contract, so that you don't get a surprise bill after the rental, accusing you of causing it.
For more tips from Edmunds.com "Confessions of a Rental Car Agent," click here.