Everyone looks for the pricing guide, I know we do.
Open Blog is free to download, use, and modify however you wish. There's no restrictions on any of that. We released Open Blog under the MIT license and there are very few restrictions. Basically, you do whatever you want with the software, you just have to leave the license in any copies, you can't call any products you make with it 'Open Blog' and you agree not to sue us if you mis-use the software. That's it.
We'll be providing support and services surrounding Open Blog soon which may incur some cost, but the software will always be free.