I picked up a 'Labtec media wireless desktop 800' at RadioShack the other day for $9.99. It's a basic wireless keyboard/mouse combo with a USB mini-receiver. The range isn't that great but it works perfectly with the Wii. It's part number 920-000294, just make sure you get the USB version. It comes with batteries and a USB extension cable and the mouse is a decent 1000-dpi optical version if you want to use it with your PC.
