What kind of USB to HDMI cable can I get for a good price?

The cheapest way to connect USB to HDMI, that won't cause significant quality loss, is to use a USB to DVI adapter and a separate RCA Stereo Cable to handle the audio.

This solution will only work if your HDTV accepts DVI and dual RCA (red and white). If it has  DVI input it probably does accept RCA and this is the best (and cheapest option) for you. You can also purchase the Atlona HDPiX USV to HDMI, Integrated Audio.  Once its hooked up, install the driver on your computer with the included CD, then connect it to your computer using the included USB and 3.5mm audio cables. The converter gets the video data through your USB port using the DisplayLink chip, and integrates the audio, giving you a single HDMI line to your HDTV with both audio and video.