It is important to remember that these prices may not stand. These are just prices retailers are throwing on them for now, and may or may not be the official retail price decided on by publisher Activision.
Amazon.com lists DJ Hero for $119.99, with the turntable peripheral bundled in. The game is slated for release in October.
European retailers have also put prices on the upcoming Band Heroes. Check out GameIndustry.biz for more on that.