Went into the local Staples (Hayes Bridge) and saw this. Don't know if it's nationwide but could be.
Canon CL-41 Chromalife Pack - reduced from £14.52 to £7.26. The pack includes a CL-41 high capacity 3-colour cartridge plus 100 sheets of 15cmX10cm (6"X4") glossy photo paper.
The cartridge on its own is £17.99 at Staples online (and I think even more in store), so it's less than half price.
I bought 2 of these and there seems to be a promotion running as the receipt says "Buy 1, get 1 for 30% off" which brought the total down to £12.34 or £6.17 each.
No expiry date shown on the pack.