Instead of complaining about them...or stealing from them (changing price tags).... how about committing to not buy from them until they change their practices:
Letter to Wal-Mart CEO
http://www.monsterfishkeepers.com/forums/showthread.php?t=184151
Letter to Wal-Mart CEO
http://www.monsterfishkeepers.com/forums/showthread.php?t=184151