The Sweex LB000021 is about the cheapest hardware router one can get. I bought mine for E25,- new. The fun thing about these routers is that there's a complete MIPS-architecture processor in it, the ADM5120, which runs Linux. One of the features of the ADM5120 is that it has an onboard USB-hostcontroller. In the LB000021, however, this feature is not used.
http://spritesmods.com/?art=sweexusb