Vince, I think I know where you are coming from. It's the result of a good business mind. You find yourself in the midst of a good situation and want to maximize your opportunity.
I would try to feel out the other guy's take on the situation. Stop by with what ever offering you choose. Don't go overboard with how great everything is working out. You appreciate the gesture. If they get the sense you are benifitting tremedously, the focus could shift to you and your profits. Keep it on them, how great they, etc. I'm not talking a big butt-kissing session here. I just think of it this way; what reason would keep them dong this? If they know it is putting money in your pocket, or they know that it makes your day?
Dnk, I had to laugh at your suggestion of cash and wonder if we are related. My dad's side of the family was big on cash and at Christmas time we'd all exchange cards with cash. Then we would joke about who came out ahead. I don't remember ever having to return or not use it though.... I can't argue with the universality. One thing I worry about though with cash is that too little could seem odd or insulting. If someone walked up to me and said they apprciated "x" and gave me $5, I'd still take it, but unfortunatly I might be thinking "$5 ain't gonna cover it" , but $5 for coffee and I'd be thinking about my next fix. Sometimes you get more bang for the buck without the cash.
But back to Vince, feel out the situation and don't attempt to formalize the situation until you see a real need to. If begining a relationship with these people is what started it, cultivate that, and if the need for a formal agreement arises, you could probably hammer out better terms with a "buddy". (not always true. good luck)
[This message has been edited by Jps1006 (edited 11-03-2005).]