one of our beardies was bought from a local pet store and is/has always been healthy. Other people, however, have gotten very sick beardies from chain pet stores. They often sell beardies that may have viruses, parasites, are housed in awful conditions, and are too young to be sold. I would not buy a beardie under 6". Also, if you do buy a petstore beardie, look for the most active one.
Sara