http://www.bestbuy.com/site/olspage.jsp?skuId=7547407&productCategoryId=pcmcat66900050002&type=product&tab=4&id=1128337921969
$14.99 after GGC* coupon (provided it's the same price in-store, which it should be).
Great price after GGC for a 360 game. I'm a big fan of the PSP Ridge Racer after picking it up cheap at GameRush so I think I'll pick this up, I played the demo and thought it was pretty good and it should serve as a nice stopgap for me until PGR3 drops to $19.99 which should be pretty soon as well.
* Best Buy Gamer Gift Card Explained:
http://www.cheapassgamer.com/forums/showthread.php?t=73
Edit: The PriceGrabber rebate is now gone.
http://www.pricegrabber.com/rating_getprodrev.php/product_id=14061514/id_type=M/form_keyword=ridge%20racer
Also availabe at EB/GameStop (user coupon code FREESHIPALL):
http://www.gamestop.com/product.asp?product%5Fid=200129
and Circuit City
http://www.circuitcity.com/ssm/Ridge-Racer-6-Xbox-360-/sem/rpsm/oid/139318/catOid/-15584/rpem/ccd/productDetail.do