Typically found under the complete name "USB 2.0 802.11b / g 54Mbps Wireless Network Adapter" and usually sells for less than $10USD everywhere you find it, this generic-as-it-gets adapter is based on the Ralink RT2070 chip (though it looks like RT2070t is etched on top of the chip). It's detected under BT5R2 and 5R3 as "Ralink RT2870/3070" and uses the rt2800usb driver.

Packet injection and AP work without any problem.