The desktop version is free, but supports only one user.
Server edition: Pricing | Manager can support any number of users and you host it on your own server.
Cloud edition: Pricing | Manager is already installed and ready to go, for any number of users.
You do not need a distributor, just select the product you want and set it up.
Once you have the desktop or server version installed (requires internet to download), it will run perfectly well without internet. (Certain functions will not work, like emailing).
The built in reports are very clear, informative and easy to generate. If you require more control over the report/graphs etc, you can export any of the reports to a format that Excel can import (tsv).
More information can be found at the links provided.