HITTING the road this summer? Better get booking.

As the busy summer car-rental season begins, prices are expected to climb. “In early June through the end of August, these rates will spike,” said Neil Abrams, president of Abrams Consulting Group, which tracks the car rental industry. Last July, for example, the average rate for a weekly airport rental of a compact car booked seven days ahead was $369.62, or 56 percent more than the $236.73 charged in March, according to the Abrams Travel Data Index. Here are some tips to keep costs down.

Let go of name brands. Look beyond Avis, Hertz and other big national chains to independent agencies like Payless and Fox Rent a Car. Because of lower operating costs, their cars, which can be found at Web sites like CarRentals.com and CarRentalExpress.com, typically cost 15 to 30 percent less than rentals from mainstream agencies. Another company with an unfamiliar name, at least to most Americans, is the German agency Sixt, which has begun opening branches in the southeastern United States, including in Atlanta, Miami and Orlando, Fla. To boost brand recognition, the company, whose fleet includes BMWs, Mercedes-Benzes and Volkswagens, is offering deep discounts. For example, a Mercedes C-class cost $38.81 a day in late May at Sixt’s Orlando airport location, according to a recent search. By comparison, the lowest rate offered by Hertz for the same dates was $50.57 a day for a Kia Rio or similar economy car.

Dig for virtual discounts. Search for discounts and coupons on sites like Promotionalcodes.com and CouponWinner.com, or type in the name of a rental company and “coupon code” into Google to see what turns up. Rental car companies offer discount codes to members of frequent flier programs, and other organizations they partner with, including AAA, Costco and BJ’s, so check those sites if you’re a member. But don’t stop there. Most major car rental companies allow you to combine discount codes with a coupon code. For example, a full-size car from Hertz over Memorial Day weekend at Washington Dulles airport was $255.71 in a recent search. Plugging in the discount code 62455 for United Airlines frequent fliers and Hertz’s promotional coupon code, 168210, brought the price down to $160.02.

Track rates through Autoslash.com. This site, which continually checks for lower rates and coupons until your trip date, can be used in one of two ways: You can track the price of a rental booked elsewhere, or you can book directly through Autoslash, which currently works with Payless, Sixt, Fox and E-Z Rent-A-Car, and the site will apply any discounts it finds.