Do any of you, particularily wedding videographers, pay a referal fee to people who send business to you? If so, how much do you pay?

I have a photo studio thats actually sends me about 12-15 weddings a year so when my sons got married last year, they 1st gave me a real good deal and 2nd, I generally pay them about 10-15% of my total charge. It varies, because I have a graduated scale. Get me X number and I'll pay this, get me Y number and I'll pay more. It's worth it to me as these are jobs I probably wouldn't have otherwise and because it's a % not a fixed $ amount, I'm not really getting hurt money wise. I have another source that sends me about the same # and they get a fixed amount. Different people, different deal. It does come out to about 10%.
Hope this helps
Don