I realise this isnt as good as the Game deal, but it's always out of stock, so for those of you who missed out:
There was a stack of guitars marked as pre-owned for £17.99; I asked about a guarantee / warantee and the assitant said it's 6 months but the guitars are brand - new anyway. Apparently they got loads in for rental but were never used.
Also I picked up Guitar Hero 3, pre-owned for £7.99 (so £17.99 + £7.99 = £25.98).
This was in the Biggleswade Blockbuster but should imagine this price is nationwide subject to availability.