Here's a very informative article regarding fabric grades:
http://craftblog.stitchingthenightaw...al-or-no-deal/
I shop on-line, at my LQS, and I also shop at JoAnn Fabrics and Wal-Mart. There’s nothing wrong with this, you just have to know how to recognize quality when you see it - When I was learning to sew clothing, I was taught the "feel test" and it works for me!
Another rule of thumb, if I hold the fabric up and can see through it then I don't buy it! The majority of the time these fabrics will not hold up and often end up mis-shapen after washing.
Just my 2-cents...
MERRYJ: Speaking solely for myself - when I order on-line I usually stick to fabric makers I know and have "felt" before :lol: I've not purchased anything on-line, knock on wood, that wasn't quality fabric.
EBONY:
http://www.FabShopHop.com has a good list. It's a start :)
http://www.fabshophop.com/listofshops.asp