If you get paid, it is commercial flying, and counts against 121 daily/weekly/monthly/annual flight time limits and probably against daily duty time limits.
I take the view that instruction provided to my friends/family for no charge is not really commercial flying any more than a $100 hamburger is, but I have heard different opinions on this. I doubt the FAA would have the slightest interest if you were not getting compensated....however if you were obviously providing free instruction to the general public to build PIC time that might be a problem (the flight time might count as compensation). For me it would be pretty hard to seriously make a case that I need any more ASEL PIC...