I researched them awhile ago. If I recall, they're $300and up.

Here are some sites I bookmarked that you might find helpful:
http://search.centralpets.com/pages/.../SNK5770.shtml
http://www.boakingdom.com/mandarin.html
http://www.proexotics.com/care_mandarin.html


Breeders (don't know if they have any right now):
http://www.proexotics.com/ca_colubrids.html
http://www.xtremereptiles.com/
http://www.snakemuseum.com/index2.htm
http://www.cunninghamselaphe.com/index.html
http://www.nwherp.com/
http://www.pythons.com/hamper/avail.html

Other than Don Hamper and Proexotics (who are highly recommended from what I've head), I don't know anything about the breeders above.