So here are so hard number and estimates. I just wanted to post these based on my experience as a developer and a game server admin. It is very important to point out how wildly this can vary so if the servers come out and they are $10/month, we can all celebrate. If they end up being $50/month (or more), hopefully this will help you understand and not just go “where did that come from?”
Scalable: $10/month for a 8-10 player limit and +$2-5/month more to increase the player cap
This is if we can choose “how big” of a server we want and essentially choose the player cap for the world.
Fixed: $50-$80/month for dedicated hosts, $150+/month for cloud hosts.
This is if we cannot choose the player cap for the world and we are just straight up given a server that is the same cap as publics (80 players). The different prices for dedicated/cloud also depends on if they are going to use a dedicated host (like Nitrado) or a cloud host (like AWS).
More Details:
Server hosting has two really big factors: are you going dedicated vs. cloud and how much resources do you need.
Dedicated hosts also come in two varieties. Managed hosts and unmanaged hosts. Traditionally, when you talk about “game servers” you are usually talking about managed dedicated hosts. Examples include things like Minecraft Realms, Nitrado, CreeperHost, etc. Single purpose managed hosts (like for game servers) can be pretty cheap. The reason is the all of the software is already built and put together to specifically manage that game. Multi-purpose managed hosts can be pretty expensive. The can get into cloud costs (more on that later). Unmanaged dedicated hosts (examples: OVH, SoYouStart) can be pretty cheap as well. The reason being is because there is no software/support provided to the buyer; they are just server sitting somewhere connected to the Internet and you have to do the rest. As a result unmanaged hosts also require some expert knowledge to use.
The devs partnering with a single purpose managed host “game server” company like Nitrado or using an unmanaged hosts seem like very likely options here. A single purpose managed host would lead to the lowest possible prices (the $10/month for 10 people and then $1-2/month more per person). Unmanaged hosts will likely lead to the lower end of the “fixed” prices of $50/month. Minecraft and ARK: Survival Evolved are two games that are great examples that use this approach. These games also have cross platform player owned servers as well. I am not a game dev and I do not know what the devs financials look like, but this is definitely the direct I would go in for player owned servers to reduce the costs to end user.
Sources:
https://server.nitrado.net/usa/order-gameserver/2
https://www.minecraft.net/en-us/realms-for-java/plans
https://www.ovh.com/world/dedicated-servers/
Cloud hosts are where the prices really start to go up fast. They are similar to how a multi-purpose managed dedicated host would be. The issue here is that it is 100% managed for any possible use case. For cloud, you literally pay by the second that the server is running. In return, you get wonderfully great developer friendly APIs that let you bring up servers at the drop of a hat and you never have to worry about data loss (outside of developer error). The nice thing about cloud is for the lower ends, you can still get those nice cheap prices (~$10/month for ~8 players), but it is going to scale up at a much more expensive rate (~$5/month per 2 players) resulting in the ~$150/month (or more!) for a full fledged game server. This prices can be reduced greatly via reservations (promising this server will run for X amount of time), but those are really hard to for player subscription based stuff since reservations are usually in increments of a year at a time.
Cloud hosts still seem like a very likely option because it seems like that is what all of the existing gameservers use (you can do a whois on an IP address of a game server and see the IP is owned by Amazon). Also, AWS is very popular amount developers. An example of another game that does this for “player owned servers” is Fallout 76.
Sources:
https://calculator.aws/#/estimate?id=a402e9208f57621d9b10aebb6bd5333434b691f8