I always use the I-95 guides you can find at gas stations along 95 and at places like waffle house and chain restaraunts.
They have coupons for hotels that run from $21 and up. You can't make reservations for any of these places they are available for rooms that are empty that night.
I look at the hotels at the exit I plan on stopping and clal them from the car to see if they have rooms available. If they do I tell them I have a coupon from the I-95 guide and hold a room.
You are taking a chance that the place might be run down, but I stay at the chain places (Embassy, Clarion, etc...) rather than a place I have never heard about (Thunderbird???)