Jim,

You are being greedy

...Seriously though you should be looking at ebay and all the fabric stores in your area on a very regular basis. The clearance bin is your friend in these matters. I seen enough posts that talk about a great find of tartan but fortune is going to favor the patient and the persistent (just like fishing).
Also regularly check out all the kilt shops online (Scottish Tartan Museum Gift Store, Celtic Croft, etc) many have clearance tartan. I don't know if you can get as low as you are looking, but there are bargins out there. Good hunting.

Cheers