Try looking around in Arlington & Alexandria. I'm not sure about crashpads, but I know that you can find some decent places to rent a bedroom in a house of people. I actually pay just over $400 / mo. for where I live (about 5 minutes from DCA)- granted it's not a crashpad, but cheaper deals like that are out there. And, if you're not familiar with the area, yes, $400 is cheap for a room.