This site is about the different phychi versions.
As long as we're in the alpha the game will be playable for free including one free saving slot for a world. When you already purchased/donated, you'll unlock upto five more online world save slots.
Well that's our current version and as you can see we'll stay here until the basic modding-, player-, entity-, packet-, and worldsystem is established. Another goal for me and our community might be to release at least 5-10 mods/plugins to extend the game.