Barb raises a very good point: It is important to charge the 'going rate' even if you only make kilts part-time, or just as a hobby. Many individuals who work in a craft find it irritating when someone comes along and just works for 'cost' because they regard it as simply a fun past-time.

It's also worth noting that kilt-making is, for some, a family tradition and a 'culturally significant' activity. (For me it is both.) Not too many people can say that about their job, and you can't really put a price on that either.