Everyone seems to be assuming that the Park taps are heavily marked up. However I just checked and all their taps are <$12 each on Amazon. Meanwhile McMaster has an M10x1.0mm General Purpose tap for $20, and of course it's up to you to make sure you get the right size, thread pitch, and style. So Park is not a bad deal in this case. Maybe the more expensive ones will last longer or cut better threads in a new hole (or maybe not), but most users are probably just chasing existing threads anyway. And it's guaranteed that you didn't accidentally order the wrong thread pitch (or whatever), because they don't sell anything with the wrong thread pitch.