Longwinded but I will try and explain as best as I can. Argos have an offer on for 20% off all bathroom products wys £25 or more in the get deal section using code BATH20 but within those 1506 items there are lots of items on buy 2 for £15 the most expensive being £12.99 each for a pair of bath sheets available in loads of different colours.
So if you add 4 of the £12.99 products on 2 for £15 it comes to £30 instead of £51.96 then add the BATH20 code and it takes a further £6 off making it £24 for 8 bath sheets which works out at £3 each - see screen shot below.



If you don't have a use for 8 bath sheets there are literally loads of items on 2 for £15 including toilet seats, laundry baskets, high quality single bath sheets, mirrors, toilet brush sets, scales, towel and toilet roll holders, bath mats, pedestal sets - loads. Get deal take you to all 1506 items that are in the extra 20% offer sorted from price low to high so just scroll through and find what you want in the 2 for £15 section which has it in red to the top right of the products image