My wife booked a half-day wading trip for me a few years ago in NC. We were strapped for cash most of the time. The guide taught me alot that got me over the hump in my learning process. I'd easily have tipped him more than I could afford if I had had it.

Guides charge a few for their service to make a living. Tips are required, they are a way of saying thank you for providing excellent service. Pay them what you think they deserve and maybe throw in a six-pack. Let them know you appreciated them or not.