90% off sounds a little exaggerated. I bought one from Target clearance for $40 a while back, it's worked nicely.
Sold by the Geeks at amazon, no tax.

or Geeks' direct link

Product Description
Bluetooth connection kit for home stereo systems * for all MP3 players and portable media players * includes wireless transmitter with built-in, rechargeable battery * includes holders for iPods, video iPods and iPod mini * includes adhesive clip for iPod nano and other brands of MP3 players * Bluetooth 1.2 compliant * 15 hours playing time with transmitter's built-in rechargeable battery *

Correction, they still charge tax if order thru Amazon.

Fixed link.

thanks!