I agree with all that has been said so far. When I started quilting, I bought the cheaper fabric and didn't feel so bad when I messed up. But, realized when I started the actual "quilting" on the cheaper fabric, it would stretch causing puckers and overlaps. If I buy JoAnns fabric now, I only buy the higher end fabrics (Debbie Mumm, Legacy Studio, Heidi Katz (I think that's her name) and if not on sale, use my 40-50% coupon. I also have a LQS that always offers 25% off 1/2+ yard cuts so that's awesome.
Bottomline, buy cheaper fabric to practice on but buy best fabric you can afford for more precious projects. You're better off have a smaller stash of quality fabric than large stash of cheaper fabric you'll regret in time.
Hope this helps.