I referred my friends to locums jobs a few years ago.
I got $2k per every 4 weeks they worked locums, max of $10k per doc.
I made a total of $16k off them! And I told them about it while doing it so nothing shady. I gave back on of my friends $1000 cash. Gave another a $500 engraved iPod touch (when they were spanking new and expensive back in early 2008). But that's for locums
They usually referral fee for full-time referral contract is usually $15-20k for an MD. That's why if you look for a job, try to find the direct source (group, hospital) instead of using recruiters because their finders fee may make you a less attractive candidate than someone without a recruiters fee.