There are a few hotels outside of Walt Disney World with rack rates of around $100.00 per night, according to the 2006 Unofficial Guide to Walt Disney World, pages 212-243. According to their top 30 best deals, Westgate Lakes at 10000 Turkey Lake Road, Orlando, FL 32819; http://www.westgateresorts.com/; is one of the best hotels out there with rates of less than $100/night. According to the Guide, you can get to any of the parks in 20 minutes or less.
I'd try the Hilton in DTD, you can get a king room with an Internet rate of under $100 a night sometimes. It's very nice and some rooms have a fireworks view.
don't stay at Westgate - their salespeople are the worst. now if you can get one of their deals $29 or less - then it is worth staying at. but only then.