I called in at the open day at Brunswick Organic Nursery today- an inspiring place to visit any time- and they had large plastic water butts (with tap but no stand or lid) free for a suggested £5 donation. I guess they have been donated by a garden centre. I got one which I think I will probably use for growing carrots as I have enough butts.
http://www.brunswickyork.org.uk/ (http://www.brunswickyork.org.uk/)
Bargain, wish I was close enough.