If you're focusing on price, I've had luck with Super 8s. They won't have any luxuries, but are clean enough, comfy and have good water pressure in the shower. You run the risk of rowdy neighbors, but as a rowdy myself I don't complain...

Otherwise the normal Days Inn works, or the Holiday Inns, though HI will probably be more expensive.

Honestly, on a road trip I'm just looking for a place to sleep for 8 hours, watch SportsCenter and shower and don't find it worthwhile to pay for anything more than a roach-free room.