when I started quilting a few years ago, I just bought fat quarters and calicos from Joanns because I wasn't ready yet for "good" quality fabric. And, since I'm self-taught, I used poly batting and learned real fast i don't like working with that only because of the fibers that come off while cutting. BUT, I still have that log cabin quilt after 8 years and it's still going strong.
What I've learned about over these years is that when quilting the cheaper fabric, it stretches A LOT, so you think you're doing something wrong when, in fact, it's the fabric's poor quality.
Then I discovered quality cotton. Oh, the wonderful feel of it. I only use good fabric now for quilts. Joanns does have some nice quality fabric and is affordable with coupons - Debbie Mum is nice but the Legacy Studio and there's a couple others that I consider quality.
A good online source is Fabric.com. I buy from them all the time. It's good quality quilt fabric and decent prices.
Good Luck on your journey. Quilting is a lot of fun.