My personal experience...1. It depends on your professional experience and qualification.
2. You should try to find the head hunting companies that are specialized in your domain. You can find job openings from their websites. Usually I'll email them and wait for them to call me back.
3. Free.
Good luck!
一直很好奇猎头公司是怎么运作的,每签一个人拿多少佣金?