Scientific anglers is one of the top manufacturers of fly lines but there are a couple of caveats concerning the ones at Wal-mart. The only lines I have seen there are their entry level lines which are shorter than their other lines which may not matter to you and are available only in WF floating which may or may not be what you want. They are not the latest version of their fly line but are at least as good as the top of the line version of fifteen years ago or probably less time than that. As for the ones on e-bay, many of the inexpensive ones that I have seen there appear to be older models even if they are brand new. Follow the link from the FAOL sponsors page for more information on specific lines.