Well, there are actually a few reasons...
1. Its my way of saying thank you for checking out my content.
2. Because (unlike other "guru's") I don't make all of my money teaching others how to sell (I actually run real businesses, consulting, physical products, software company, marketing company, and more)... so because of that, it doesn't hurt me to share with you my best stuff.
3. I get another one of my products in your hands, and when you see how well it works, it should get you excited to buy other stuff from me in the future.