This plugin allows you to host your own plugins on your wordpress installation.
I was working on a plugin that had a pro (paid) version. This plugin had 2 code bases and was hosted on an external site. This site charged upwards of 50% of what I was charging.
So I became interested in finding a way to provide updates and use only one code base. I also wanted to minimize the cost to sell the plugin so that the money was not going into someone elses pocket. With Sell My Plugin, you host your own plugins. You use PayPal to charge for the purchases. There is a transactions list so that you can keep track of your sales. If you sell 10 copies of your plugin in a month at $10/ea, this plugin will save you $360 per year vs PlugPress and $600 vs CodeCanyon.
This plugin also uses the familiar domain.com/extend/plugins/ layout just like wordpress.
Custom email following purchase including shortcodes to allow for injection of PayPal data!
And many more!...