It is true that many of the cotton fabrics sold at big box stores are inferior in quality although at first glance, they may "look" just like fabrics at your local quilt shop because they are often printed with some of the same designs. Don't be fooled! Of course, it depends on how you plan to use the fabric but if you are planning to put a lot of time into making a quilt as well as pay to have it machine quilted, it is advisable to use the best quality fabrics you can buy. If you plan to make crafts to sell at a fair, by their very nature, crafts are not intended to last as long as a quilt that is well-preserved.
Poor quality fabrics feel stiff to the touch because of the number of chemicals that have been added to give them more body. When washed, the fabric may revert to a very limp state. Often, poor fabrics have low thread count or are poorly woven and have snags. Some will fade more easily than others. Some will run when put in water, like there is no tomorrow!
The old saying is "You get what you pay for." In this case, it is true but not always. One of my favorite places to shop is at the Marden's stores in the state of Maine. The store buys first quality cotton on bolts from quilt shops that are going out of business and want to liquidate their entire inventory quickly. The prices are ridiculously low, far lower than even Walmart or JoAnn Fabrics, yet the quality is great.
For hand quilting, I love Northcott brand fabrics because they have such a nice weight and "feel." No, I don't work for them nor am I being paid to state this fact. Some designer brands I stay away from just because they notoriously fade and/or run and I've had bad experiences.
These days, I am making smaller quilts due to constraints of time so it is a lot easier to buy the best quality I can find. I don't want to waste my time with something that is going to look crummy just a short time later, or not stand up to use, if I give it for a gift. Not a quilt snob, but just hate to see "waste" - of any kind, including my own time.
Pat