In case you haven't heard of Greige (pronounced "grey") Goods before, it refers to the fabric before any of the dyes are added to it.
Often Griege Goods is talked about in terms of quality. For instance, "The quality of the Greige Goods...."
This summer I saw what a difference the quality of the greige goods made. I wish I had a picture to show you.
A month or so ago a lady showed me her first quilt. It was a beautiful lone star quilt. It was amazing! She was a seamstress before she was a quilter, and she took the time to make sure her piecing was precise. I couldn't believe it was her first quilt! It had also been used and loved for a few years. What was interesting to me was that I recognized many of the fabrics in the quilt. In fact, I had purchased at one time or another many of those same fabrics before I learned about quilt shop fabric.
One fabric in the quilt was quilt shop quality fabric -- which I also owned a piece of. That fabric was the only piece of fabric that hadn't faded.
Why? Because quilt shop fabric starts with a higher quality of greige goods, maybe better dyes too, I don't know about that. That's why it is more expensive. It is better quality.
I'm not saying that there's not a place for non-quilt shop fabric. Just consider your project before you use it.