Okay Assertn why would villages put bounties on people's heads and have guys at exchange points to pay guys like Kakuzu for killing people, when the villages themselves have both the means and the motive to kill them. Early in the series the Third said one of the things the villages are often hired to do is perform assassinations, so why when they themselves need someone killed would they turn to outsourcing. They couldn't possibly be making a profit by paying out millions of dollars per corpse when they could have sent their own ninjas to do the job.
Hell aren't the anbu there for the purpose of performing assassinations, I mean they are the Special Assassination and Tactical Squad after all. We already saw that Sai's job prior to joining team Kakashi was assassinating people who were deemed a threat to the village and it was said that Kakashi's raikiri was created specifically for performing assassinations.
I can't see any reason why it would be necessary for the villages to place bounties on anyone's head. Besides its not as if we've seen anything that suggests that the villages are the ones placing bounties on people heads. Its not as if Kakuzu said, X village has a bounty on your head. In fact right here its says it was an underground organization that placed the bounties on their heads.