Let me add one cautionary note, intended as a help and not a discouragement:

You've overlooked marketing.

Marketing, done properly, is involved from the first step. You don't simply create a product and then try to sell it. You find a market and create a product for that market. In this case, I would strongly suggest a little research to determine whether there is a kilt niche market that you could create a product to fill, instead of trying to compete with established companies in the same market. Price alone will not give you a competitive edge.

Marketing will also help you determine a proper price. Too low and people may automatically assume it's an inferior product. Increasing the price could actually increase sales by creating a perception of quality, and give you more room to offer special discounts, which can also increase sales.

And marketing will tell you how to, well, market the product. Do you advertise? Where? How much? Do you concentrate your ads in one region, or in one market segment? How do you know when to expand your advertising> How elaborate a website do you need? Will you wholesale or retail or both?

And when all that is in place, you can take the steps to start production.

I do marketing for a non-profit organization, but I'm far more involved in promoting the organization than in selling anything, so if I get any deeper into this I'm probably out of my league. But I hope this is helpful.