One good source if you are an AAA member is the Tourbooks, which are published by region. I used mine on my last road trip to find the next Motel 6, and the price range. Each listing usually contains either their seasonal price ranges or their per-person ranges. I'm finding that in planning my next trip, its providing a great way to find some 'mom and pop' motels that have been rated and approved by the association.

The articles/posts on this website are also GREAT help too!