Terasology(/r/Tersology) Is an amazing open source alternative.
>Terasology is a game that pays ample tribute to Minecraft in initial look and origin, but stakes out its own niche by adopting the NPC-helper and caretaker feel from such games as Dwarf Fortress and Dungeon Keeper.
Go take a look! :)
We use OVH.com for hosting multiple modded servers. 1 box with 64GB ram 1TB HDD 110$/month. They recently added smaller boxes with Core i7 for less money. https://www.ovh.com/ca/en/dedicated-servers/game/