First of all, welcome to our rabble

Inexpensive is a very relative term. But, there are a couple of places that the vast majority of the members here (myself included) fully support. Try USA Kilts . You can purchase one of their "Casual" models for $110-$130. USA Kilts uses a poly/visc material that's awesome (especially for the price) and he has numerous tartans to choose from. I would recommend calling Rocky (USA Kilts) up and chatting, he'll square you up.
Another good place for an "inexpensive" kilt is Stillwater Kilts. You can find acrylic kilts there from $40-$80. They also offer a line of heavy wool kilts for around $150 or so... though I think there's still a sale going on. None-the-less, good luck in your searchings. Don't be a stranger.