Air Display to Virtually Connect Multiple Devices

You will notice that I try very hard to stay away from products that cost money for this blog.  But here is one that just might be worth it.  Many people like to buy a cable to connect their laptop to a second screen.  Well using Air Display, you need only download the software onto two devices and you can virtually connect them together.  It is not free, but then again, neither is buying a second screen and cable when you probably already have two devices.  You can use a tablet, smartphone or laptop and can mix Android and Mac devices if you need to do so.