I went to Highland Fling's web site and couldn't see any information about their kilts at all, so I cannot comment on who makes them or where they are ordering them from.

However, I might be able to give you at least a basis for comparison. If you were to buy a traditional 8 yard kilt from the Scottish Tartans Museum gift shop, made by Lochcarron of Scotland (who do a superb job on their kilts, which is why we use them as our preferred kilt makers for most jobs), you'd have your choice between 10 oz (light weight) and 16 oz (heavy weight).

The heavy weight would be the best quality kilt, and my personal preference. You'd have your choice between Burnett modern, ancient, or weathered. The cost would be $629 (based on average measurements).

If you wanted a less expensive kilt, the light weight cloth is available in Burnett modern only, and would cost you $495 (again, based on average measurements).

The House of Edgar also produces the Burnett tartan, in a 13 oz (medium weight). The museum gift shop could also supply one of their kilts. You'd have your choice between ancient and modern colors, and the kilt would cost $527 (based on average measurements).

I would bet that Highland Fling is obtaining their cloth from one of the two above mentioned mills, and if they don't have their own in-house kiltmaker, they are probably getting their kilts from the same source. The prices I gave you from the Scottish Tartans Museum represent a pretty minimal mark-up cost. So if they are quoting you upwards of $600, it's probably a pretty fair price, especially if that is for Lochcarron's heavy weight range, which would be the highest quality, but also the most expensive option.

Oh, and if you want sample swatches, I would assume Highland Fling could order them for you, but if they can't, you can order them over our web site, here:
http://giftshop.scottishtartans.org/material.html

Or just give us a call at 828-524-7472.
Aye,
Matt