As Jock Scot and others have said, the most economical kilt jacket to own is an Argyll jacket in black barathea. What you want to do is order it with a three-button waistcoat so that it can be worn with black tie. For some reason (probably because they can get away with it) these waistcoats cost a bomb. Okay. So be it. The five button waistcoats also cost a bomb, but for what they cost you could have your silver buttons made interchangeable with black leather knotted buttons by a local tailor/seamstress/alteration shop, pick up a black wool five button waistcoat at your local thrift store, and still have enough cash left over for a Dr. Pepper and a package of Twinkies. (Dr. Pepper and Twinkies? Perhaps I've been in America too long...)

Even without changing the buttons, an Argyll is the only jacket that is appropriate for both day wear, evening wear, and formal evening wear simply by changing your tie.