How do bounties work in the Star Wars universe around the time of the Galactic Civil War?

Bounty Hunters usually choose the side that pays the the most. (the jedi don't hire bounty hunters, and i can't come up with a time when the senate did either.) This is usually the separatists. so you can consider Bounty Hunters bad guys.
Most bounty hunters learn to cope on their own, but when an offer is given to them they almost always take it up.