I'm new to quilting but I did just purchase a bunch of different ones for a quilt I am now working on. I was lucky and got them at 40% off at Joann's. I was thrilled since this is my first quilt keeping the cost to a minimum would be good. I did purchase some fabric from bolts for the trim and two other fabrics. My total was under 75.00 That did not include my batting or the back fabric but I thought this was great.
I'd say that if you can get them on sale and they will work for your pattern then its worth looking into due to the fabric savings.
Diane