In Play.com's 25% off deal. It's possible to find it cheaper somewhere else but this is a good price from an established retailer.
The epic saga continues with Halo 3, the hugely anticipated third chapter in the highly successful and critically acclaimed Halo franchise. Master Chief returns to finish the fight, bringing the epic conflict between the Covenant, the Flood, and the entire human race to a dramatic, pulse-pounding climax.
Taking full advantage of the power of Xbox 360, Halo 3 expands on everything that has made the Halo franchise great, adding a wealth of graphical, technical and gameplay advancements, as well as offering a whole new level of online gameplay.