When our quilt guild had a LQS owner teach a class, she admired one of my fabrics. It was a really nice fabric by South Seas and before I thought about who I was talking to I told her it was from Walmart. LOL she told me to bite my tongue.
I buy mostly from quilt shops but in truth I buy everywhere.
I have been sewing forever and have enough experience to tell the difference between good quality and not so good but once in a while I get stung and sometimes it has been in the LQS.