As a part-time sporran-maker myself, I'd say that the first question you need to ask yourself is: do I want to run this as a business or as a lucrative hobby? For me it's a lucrative hobby, in the sense that it covers my materials and the time is spend making each item. I enjoy myself, have relatively little pressure and have some money to go to the restaurant/buy beer. A business is a whole different prospect: you're depending on it for your livelihood and have a whole lot of other costs and factors to put into the equation...