Both sides of my family has always been given something from the hunter's neck of the woods (like a bunch of jerky, or a hunter's recipe summer sausage, knives...stuff like that) or like a jacket if the hunter has his own outfitting service elsewhere. I have even witnessed the trading of hunts the next time around. I don't think I have ever seen them accept tips. If I were to tip a guide, though, I would say $100 sounds reasonable.