£3.60 for 5 litres of white adhesive and grout. Seems like a bargain to me...
Quick search online suggest this sells for around £20 usually.
5 litres does 4.1 square metres according to the tub
Bought 3 at Sheffield Catcliffe store today - they had a pallet of about 50 tubs.
Good deal if you have a JRF near you http://www.jtfmegadiscountwarehouse.co.uk/branch-locator.php
just remember to being proof of address if you are not a member (it is free to join)