Seems to go for less than $100K USD, which surprised me (source is Australian though http://edition.cnn.com/2004/WORLD/asiapcf/02/05/australia.ki...)
The Wikipedia page has more info on "contract killing", won't put you on a list to just read that :) https://en.wikipedia.org/wiki/Contract_killing
Since this murder-for-hire chose to use a global and transparent ledger that will have that transaction until either the world disappears or the ledger somehow disappears from all nodes, I don't think "smarter" should come anywhere near this. Using blockchains like Bitcoin for crime is far beyond stupid.