Finding a USB or Ethernet wifi adapter comp w/Mountain Lion

Where I live/work I only have access the kind of internet that hotels use. I have to login with each device to access the internet, and only one device at a time. This is a bummer, I used to use connectify but wifi - wifi on mountain lions built in router isn't an option. Up until lately I have been able to logon to my internet through hardwire (ethernet). I just moved rooms and this room has no ethernet hookup, so I am looking for a small usb wifi adapter. I hope this would work that then I could choose to use my computer as a router by way of USB to WIFI.

Has anyone used one that is easily compatible with Mountain Lion?

Thanks