Try Enterprise Rent-a-Car. They usually have about the lowest rates as well as the kind of car your looking for. I got a Dodge Charger from them back in July.
Yes, Enterprise seems to be consistently the lowest priced around here, and seem quite customer friendly in terms of service. And easy to check online.
Because of industry consolidation most of the various rental companies are actually owned by 2 or 3 mega firms. But each brand has it's own marketing niche.