Unfortunately they are still a specialty item, and therefore a Walmart version has not come out yet. Besides ebay, converting a regular sport coat, or ordering a real one, most people are SOL. They are after all meant for Highalnd dress, not use for everyone on a day to day basis (with trousers). It's the same reason traditional kilts are still fairly expensive.

I am sure that someone will come up with a really cheap jacket to go with the cheaper styles of kilts these days, it just hasn't happned yet. Who will be the first?