I have a "Prince Charlie" that I had cut down from a formal tail coat. It takes a minimum of tailoring, and only the buttons cost much of anything.

You can purchase a used tail coat from several sites on the internet at a very modest cost; it just takes some looking. Of course, you can pull of the same thing with a black jacket from a suit or tux if you can find one that is very plain. A tailor can easily cut it down for use with a kilt.

But as Jock pointed out, a black barathea argyl may be a better alternative to a PC as it can do double duty. It all depends on your own taste, your needs, and your purse.