Amazon have an offer on at the mo. If you buy the Brita Maxtra 3 pack of Filter Cartridges priced at £10.47 and then add the Brita Spacesaver Cool White Water Filter Jug, priced at £11.57 you get it for free. Thanks to tkpeters for the heads up on this - the FREE Super Saver Delivery option works on this as it offers it BEFORE the discounts are taken off during checkout. Each Filter Jug comes with a cartridge, so this means you get 4 Maxtra cartridges and the Brita filter jug for £10.47 Delivered - a bargain! EDIT - RICKYM has just pointed out that if you order 2 lots at the same time it only deducts the price of 1 of the jugs so comes to 32.51! Thanks for the pointer ;)
I've done a direct link to the filter jug. Underneath the picture is the heading 'Product Promotions' and you can link to the deal from there.