You're right in the neighborhood of a fair price at $3.50.  Why don't you consider yourself a "professional" after sharpening chains for 10 years ?? 

"Still not looking to make money, but want to continue to help out my neighbors and friends without giving my work away too cheaply."  Well if you want to continue helping out neighbors and friends why not just continue as you are? 

I'm "old school" I guess,, I just put the bar in the bench vise, tighten the chain real tight to take out the "file chatter" and hand sharpen my saws. It takes about 20 minutes but, my chains last alot longer than using a grinder type saw sharpener.

Just my theory about friends/neighbors,, but I don't ever want them to feel like they ever got less than a fair friend/neighbor deal from me. If they weren't a friend or neighbor they probably haven't ever met me anyway.