Alright, felt bad about that last post so I went out and searched. This is the cheapest dual band I can find for you. $27.99, Rosewill RNX-N600PCE, Dual Band Wireless N600 Wi-Fi Adapter
Edimax isn't a big name, but they are actually a board-assembler, delivering products to some more popularly-recognized resellers (Asus, Rosewill, Zyxel, for example).