It doesn’t happen very often, but it does happen: You get stuck with a non-refundable hotel room you can’t use and you have to hide the credit card bill to avoid the shame. Roomer buys and sells hotel rooms in cities all over the world, with a high concentration in the U.S. It works in more of less the same way StubHub.com sells off theatre tickets. You submit your unused hotel reservation, they post it and you get paid when someone buys it. Best of all, it works both ways, a boon to bargain-seekers looking for a room, if you can handle the last-minute-ness of it all. Visit Roomertravel.com.