PrettyPress has two primary versions, free and pro.
The free version, is licensed under the MIT license and can be used for no cost.
The pro version, is copyrighted and a valid license must be purchased for use.
PrettyPress Pro licensing
PrettyPress Pro has multiple levels of licensing available.
Personal – $10
You are free to use PrettyPress on any number of personal websites.
Developer – $50
You are free to use PrettyPress on any number of commercial websites that you sell, however, you may not redistribute PrettyPress within a theme or plugin you are selling online. (This includes market places like ThemeForest and others)
Commercial – $150
You are free to use, redistribute and package PrettyPress on any website, theme or plugin that you wish to use or sell.