Recently picked up a used 2010 Prius that has an aftermarket headunit. I went to revert it back to the stock Prius II headunit, but only if its cheap enough. People that have upgraded your headunits.. sell me your stock headunit for cheap! Prefer so-cal for a local pickup, but probably willing to pay for shipping as well if the price is right.
You might want to check eBay. There are quite a few available around the $80 range and you can even make offers. Here is a JBL unit with CD changer with no reserve: New 2010 2011 Toyota Prius JBL Radio Stereo 6 Disc Changer CD Player | eBay
