+ 1 for the Big Agnes. I now bring mine on trips where otherwise I'd be sleeping on a couch or pullout, even with a car or plane trip, because it's more comfortable than bad beds and really packable. Might be out of your price range, but definitely best value for the dollar. Otherwise I'd say definitely look to borrow or rent. I wouldn't go without something - important for comfort, keeping your bag away from dirt/dew, etc.