Kopparberg Pear 500ml bottles are part of the more general 3 for £4 deal (26.7p/100ml) that keeps appearing and disappearing at Tesco. Current offer expires 11/07. Asda are slightly more expensive at 2 for £3 but their deal lasts into mid-August. Only problem is that shelf space for Kopparberg products is very limited so you have to be lucky to find some. There will no doubt be acres of lesser pear ciders!
Although it's not for me, if you like the canned version, you can get 24x 330ml cans for £16 (20.2p/100ml) or 8x 500ml cans for £9 (22.5p/100ml)