I tried to buy a new jug, the webpage said 'Save £5 when you buy a Maxtra 6 pack (original price £16.99) with this jug.' So I added the filter pack in my trolley.
When I checked out, the total was only £24.38, £7 saved, rather than £5
Brita Maxtra 6 Pack Replacement Water Filter Cartridges. £9.99
Brita Fjord White Water Filter Jug. £14.39http://www.argos.co.uk/static/Product/partNumber/8422776.htm