I recently saw that www.libertyfund.org sells a complete collected works collection of his work here:
http://libertyfund.org/details.asp?displayID=1598
I know nothing about James M. Buchanan besides that he was one of the central figures in the school of economics “Public Choice”, about which I also know nothing.
Is his work worth reading? If so, which volume(s) represent(s) his most important or worthwhile work or contributions to economics?
He has some interesting articles, but - as far as my opinion goes - he repeats a lot, which tends to be annoying after a while.
His books can be interesting, if you are interested in a more fundamental approach to the literature. I would recommend not to buy them; but first try to read some of it from your university library or something.
‘The Limits of Liberty’ & ‘cost and choice’ are (imo) the most interesting 2. (This is because I disagree with his emphasis on ‘constitutinalism’ and stuff; which is a big part of his work.)