Yes because it is not 300 bucks, it is 500. They come in 2 packs only. Further they expire after one year, so its 500/year. Further still many people buy more than just 2, since it is more about having one within easy reach. So often people buy 4 (2 pair) so now we are talking a grand a year difference. Some people just don't have a grand to spare so they were doing without. Lastly, if FDA said it was good enough, its as good as the name brand.