Fallout 3 Goty for 360 is £7.98 Pre-owned at the moment. its in their Easter sale.
I found it in Milton Keynes. I got the last one though, but you might be able to get it in an other Gamestation.
Edit - I just looked on the xbox forums, as i was going to post on their too, and their is employee on their confirming this deal in another store. so looks nationwide if you get them instock.