I have read online that you should start at half the caddie fee and then adjust based upon how good they were.
The caddie master should be able to tell you the required rate, and the tip is up to you. For example, our required rate is $35.00. Anything above that is considered a tip. The kids who are mules (bag-carriers) usually get no more than $50.00 total, and the caddies who really know the job get anywhere between $60-75.00. I used to be a caddie so I understand what the job entails and I tip accordingly.
I have had caddies at a lot of different courses and the bottom line is that you should never let a caddy leave the course with less than $100 cash, if he is good. Every course is run differently and the caddies are paid differently. I know for a fact that some places where you see a caddy fee, the caddy does not get paid that amount. The bottom line is this, ask the caddie what he makes. He will tell you. Yes, sometimes some will exaggerate and you can tell. But most are honest and will respect that you are asking them instead of other people that don't care about them. There shouldn't be a flat per person rate because if you go out by yourself and that is the only work he is getting for the day you should tip more than if you had a foursome, at least on a per person basis. I think a good tip for a group starts at $200 and goes up from there depending on how good he is and also on how much money you may have. Honestly if you are worth $100 million dollars, would it kill you to tip more generously? I try to tip well, people in a position that gets tips generally do not make that much money....