I'm with you Uncle Ricky...

The link Bear gave you is very, very useful, you will need to email or call to get current availability. They are also very nice and helpful. I just bought three remnants from B&S, totaling about 8 meters SW. I will have several pieces to join, but, I only paid about $60 US including shipping.

You can also try Fraser and Kirkbright for poly/wool and wool remnants:

http://www.wooltartan.com/tartans5.htm

For all the searching I have done, I think Clansman Knitwear has THE best prices I have found on new 100% wool tartan.

http://www.scottishclansman.com/Tartanyard.html