I know most people who don't live in Wakefield will vote this cold straight away (thanks for that), but if I can help a few people out then it is worth posting....
Not every council offers the same deal, but my local council (Wakefield) offer 190 litre water butts for £26.15 which seems a good deal to me.
It is worth checking you local council website to see what deals they offer
Looking online the cheapest deals seem to be around £20 for a 100 litre butt, so an extra £6.15 for the 190 litre version seems worth it, as the alternative is to purchase 2 smaller ones and link them together, but that would cost you much more.
With all the rain we have had recently, it is a good time to get one installed and stock up on supplies!