Since its founding in 2000, Hotwire has become a true heavyweight in the discounted travel scene. If you're shopping for a cheap car rental, definitely check Hotwire – but before you hit the button to finalize your reservation, take a minute to make sure you're getting the best deal possible.

Hotwire's Two Booking Methods

A standard Hotwire rental is much like dealing with any other online travel broker: You'll see which car rental company you're renting from, what type of car you're shopping for, its essential amenities and the discounted price. A Hotwire Hot Rate rental gives you access to even cheaper rates, but you won't see which company you're renting from until you finalize the booking. In either case, keep in mind that the rate you see in the initial listing doesn't include taxes. Those will be added once you select a car type.

Tools on the Hotwire Site

Three features on the Hotwire site might be able to save you money on a car rental: First, if you find a lower price on the exact same rental within 24 hours of the booking, Hotwire will pay you the difference. This "Low Price Guarantee" applies to both standard car rentals and Hot Rate cars; use a site like AutoSlash to watch for changes in price.

The second tool is price alerts; once you've set the search parameters for your car rental, you'll be prompted to enter your email address and Hotwire will email you if the price changes. And finally, although Hotwire's TripStarter feature doesn't track car prices directly, it will tell you when hotel prices go down – and it's usually a good bet that the low season for hotels will also be low season for car rental companies.

Watch Out for These Catches

Although you get the best deals with a Hot Rate rental, there are a few catches to be aware of. While some (but not all) standard Hotwire bookings can be cancelled or adjusted, all Hot Deal sales are final and must be prepaid when you book. You can't change, exchange or transfer your Hot Deal booking at all, and you can't use a loyalty club account to collect reward points or speed through the VIP line. You must have a credit card for the security deposit; you must be at least 25 years old, and the booking only covers one driver. If you want to add another driver, extra fees are up to the rental car company.

Alternatives to Hotwire

Although Hotwire often provides some of the lowest prices for car rentals, if you have a Costco membership, the prices on car rentals from Costco Travel sometimes rival those from Hotwire – and Costco's rentals are much more flexible, allowing you to cancel or change the terms of the trip. You can also save money by joining your favorite car rental company's loyalty program, joining AAA for discounted rates on car rentals, or checking if your car insurance carrier offers discounted rates with any car rental companies.