The Hut are selling "Tomb Raider: Anniversary" for the Xbox 360 for £10.93 (inc Del.)
You can also get cashback through the usual sites (e.g. 5% Quidco, making it just £10.38)
The next best price seems to be £12.97 from Tesco Jersey
Unlock the past...
When Lara Croft is hired to retrieve a mythical object called the Scion, she begins a dangerous search across isolated and desolate worlds, places untouched for thousands of years. But Lara is not alone, the tombs are guarded by fearsome creatures, and close behind are others desperate to learn the Scion's powerful secrets.