I know one consultant with a boutique firm whose contract states she gets $100 per night for staying with friends or family. I know she does this often in New York City where she stays with her daughter.

Next month, my mother has a consulting gig in DC and she is staying with me. Not for any savings (she could stay in a hotel if she wanted), but at chez humanoid she gets free internet, great metro location, and a starwood W bed.