2kg Eukanuba cat food for £1.95 at In-Excess Salisbury.
They also had all sorts of Eukanuba dog foods too.
The one which caught my eye was the hairball control one but they had other versions too.
£28 at petsathome, £16 online.
NOTE: it's probably low date (I didn't check) but eukanuba food uses the 'best before' dates which are a suggestion, not a 'use by'.