I have purchased the 108" at Joann's numerous times. It really depends on what 'brand' the fabric is. Sometimes it says Joann's Fabric on the fabric edge and sometimes it is a different brand. I have only purchased it in the store and was able to feel it before buying it. Some are thinner feeling, while others are heavier and stiffer - and both have been Joann's brand, and both have been other brands as well.
Honestly, when I buy fabric in a store that isn't a 'quilting fabric store' and more of a craft store or department store, I'll buy it in person so I know what I am getting.