Yes. The Personal and Business versions will be free forever. Gaio’s general resources are available on both. To better understand the difference between the versions, access here.
None of the versions of Gaio include servers. Therefore, you should install Gaio wherever you want it..
The monthly fee for an Enterprise license varies depending on the size of the servers to be used. For definition of the size, the client should fill out a sizing questionnaire, offered by Gaio. That way, you will be clear about the size of the server that will be adequate for your reality.