The $10 version simply gives you the addon like all other versions. It's purely for those who wish to support the development of the project.

BlenderMarket doesn't allow me to upload free addons, so $1 was the cheapest price I could set it to. But even that $1 does also support my work, so purchasing it here is greatly appreciated. However if you cannot afford that or if you simply want to get it for free, check out the github repo. The latest version will always be available there.