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.