I worked a tournament this weekend and, to show his appreciation, a customer offered me a joint after I closed shop. I respectfully declined. Not for me...
LOL, sound Like a few that I know.
Seriously though- Like Chris mentioned, I had one guy that respected the amount of work that goes into a cue, said i deserved to get paid fairly for my work, and offered me more then I was going charge to him for the cue.
Most of My work is on the repair side though, so I see more gifts from that end. Usually in the form of a cash tip, or buying me a beer at the pool hall, But I have received other things like wood, antler racks, etc. Oh I had a Lady give me a old viking cue with the window in the butt-sleeve, and It johnny Archers autograph on the forearm. It use to belong to her husband before he passed away, and She said she just wanted me to have It. I do work on her cues, have always taken care of her family's cues, but she's also a good friend, so I guess that gift may not exactly be the same as a tip for work performed.
I've also horse traded for work done before, but again that's a different thing.
I don't know about others, but to me just the act alone shows appreciation for what You do, and that has much more meaning then what type of gift It is. I've sure whatever is given will be appreciated.