Mine currently have whatever it was Morrisons was selling when I was there doing the shopping
don't go too cheap or you'll be saying your screen wash pump filter is blocked with slime
Or, like last time I used that TripleQX shite from ECP, found it froze, neat, and shagged a headlight washer, which was over £50, plus a bumper off job to fix it.
I use the Halfords Berry (-10C) concentrated stuff most of the time, 20% in summer, 100% in winter, or in Jan/Feb, the Citrus -20C stuff. Cheap enough (effectively free for me, as I have a near never ending supply of Halfords vouchers) on trade, convenient, and cashback as well (which often goes towards yet more Halfords vouchers )
I like the Blackcurrant as it smells really nice!
Small things amuse small minds......