Just came across a weaver/kiltmaker's site I'd not heard of before.
No personal experience, but their site indicates they sell their own woven tartan cloth and kilts at what appear to seem to be reasonable prices (from £126 without VAT, heavyweight casual, wool).
They also propose samples for £3, where other suppliers ask for £10 or even £15 !

<http://www.tartankilts.com/index.asp>

Unfortunately, I found this one day after ordering a second-hand kilt from e-bay -- at a higher price!

Martin S