Movie and game rental outfit, Blockbuster allows punters to swap two games out of a list of six titles and pay only 99p to get Call of Duty : Black Ops; the offer does not appear to be available online and to be fair, is not as good as the one from Currys, Tesco or even Sainsburys.
The game is normally available from Blockbuster for £44.99, which is £8 more expensive than at Tesco or Asda; as for the games that can be swapped, they include Medal of Honour, Fable 3, Fallout New Vegas, MMA, F1 2010 or Star Wars : The Force Unleashed 2.
Given that most of those games still carry some significant value, you might better sell or exchange them at CEX for Call of Duty : Black Ops. Others that have been running CoD : Black Ops include Asda with a £4.97 deal (a much better one since it involves swapping ONE rather than two games), Sainsburys where you get the game for £24.97 when you spend £30 instore.
Tesco allows you to pick up the game for £25 when you spend some dosh on some Xbox or Playstation accessories. Our favourite though remains the one from Currys where you can grab the game for £20 when you spend £50 either instore or online.