The PS3 version seems to be for the same price (why the OP only linked the 360 version is beyond me): http://www.buy.com/prod/red-dead-redemption/q/loc/108/210851865.html
The 30% off coupon only applies to the original price of the game. The 40% off promotion only applies to the sub-total. So it is not 70% off, but it's still very good--too bad we cannot triple-dip using sale prices as well.