Priceline is a good deal for rooms. I've paid $60 bucks for a room at the Sheraton in Boston and DC, and 80 bucks for Marriot rooms in NYC before. mmmm... nice plush beds and all...
check out
www.biddingfortravel.com for tips on how to bid on priceline.
Hostels and B&B's can be a good deal sometimes. Though i'd really not want to stay at a hostel if i'm traveling with my SO *WINK* . Lack of security as well. It's great fun if you're in a group, and its high season though, you can meet new people.
Get/rent a caravan?