If you pick up one of the Currys Gift Guides and register the code online that is on the back you will get at least a £5 voucher with no minimum spend. It is emailed to you within 4 days and has to be used before Christmas.
It is £12.99 without the voucher. To check stock go on the PC World or Currys website.
Can be used also to get 12 months or the 14 month halo xbox live pack for £29.99.