I used to be in a business where I bought a LOT of fabric every year, 70,000 yards the last year, so I know a good source when I find one :)
Wherehouse Fabrics, 2675 Perth St, Dallas, 75220 214-352-4908
And yes that is the correct spelling of the name

I have been there twice now, and really like some of the selection they have. The have some 90" wide goods for 3.99 a yard, 5 yd min. They also have some black poly/cotton that although not the best, would work as a BG.It's 120" wide I think it was like 4.50 a yrd.
Just thought I would let ya'll know.
Perth is off Harry Hines, about 1/2 mile S of Walnut Hill.