I'm not sure about the 50 bucks, it was three months of work...

But maybe the gentleman had a bunch of free time on his hands and just wanted something to pass the time anyway. Then 50 would seem fair enough.

In any case, I hate it when someone answers a question with a question. He doesn't want to offend you by asking for too much money, so now the ball is in your court and you don't want to offend either. Now, your conscience suffers...

Personally, I would have bought him a nice kit since he obviously likes to build.

I'm not sure if there is a right answer here. Money always seems to screw up everything.