I copied this from QuiltBug. It's worth reading and may help you in your decisions.
How do you choose the best quality fabric for your quilt? Quilt shops, magazines and patterns will tell you to always use quilt shop quality fabric, but what does that mean exactly?
To understand what "quilt shop quality" fabric is, we have to go back to the beginning. Cotton cloth before it is printed at the mill is called greige (pronounced gray) goods. The higher the thread count of the greige goods, the higher the quality of the cloth will be.
Average cotton cloth has a thread count of 60 x 60 threads to the inch, sometimes called 60 square. It may be thin or stiff and it shrinks a lot in the wash. Expect your batting to migrate or beard through these widely spaced fibers over time. Better fabric - which is what you usually find in quilt shops - has a thread count of 68 x 68 or more and is made with longer staple cotton thread. This makes it feel a little softer, accept dye better and have a longer life. It will still shrink a little in the wash, but not as much. PFD (prepared for dying) and batik fabrics can have up to a 200 thread count and generally don’t shrink at all.
The first time a mill prints cloth, they will usually do so on lesser quality greige goods in order to test the colors and the placement of the designs. Look at the selvage of fabric you have just purchased. See those color dots? They aren’t there to help you choose co-ordinating fabrics, although many people use them that way. They are there for the manufacturer to make sure the color was correct and that it printed in the correct place.
The printing process manufacturers use can be quite complicated. Fabric designers work about a year in advance to come up with the concepts which are then converted into colorized designs. These designs are sent overseas to the mills to be test printed and returned to the manufacturer for approval or correction. Most of the quilt fabric we use today has been printed in Korea or Japan. Classic Cottons is the only company that prints in the United States.
In the 1920's - 1940's, mills would test their prints on low quality greige goods. These low quality greige goods later became feedsacks. In todays market, these first run tests often become the flat folds that you purchase in discount stores. These flat folds may be printed on lesser quality fabric which won’t last, or they could be printed on good fabric but the colors and/or designs weren’t up to manufacturers specifications. Some flat folds are printed as deliberate knock-offs of a popular design. If you compare it to the original design, you will see that the colors are bit off, or a part of the design (like a leaf or a vine) is missing.
Quilt fabric also goes through a multi step finishing process, which sets the dyes and makes the fabric softer. Inexpensive fabric skips the last couple of steps, resulting in stiff fabric that wrinkles easy and is very susceptible to bleeding and/or sun fading. Fabric that is quickly printed to take advantage of a trend like hot a hot cartoon character often skips those last few steps because it is less expensive to make and manufacturers believe people buy it without planning on any long term use.
Whenever you make a quilt, use the best quality fabric you can find. Don't frustrate yourself by using second or third best. You will be happier with the process and prouder of the end result.