Good post Eddie, but booking less than 10 days ahead, right around July 4th, I'm skeptical of one's ability to secure anything quality much under $200. Could happen though, doesn't hurt to look.
There are some DT hotels under $150, but the consumer reviews tend to be poor.
And, everyone's "walking distance" is different. If your willing to be 2 or more miles away one way, you'll be able to cut down the rate while maintaining the quality. Heck, if you willing to be 7-10 miles away, you can go under $100 I'm sure.