I don't have much experience in networking, but for my upcoming game, I hope to incorporate multiplayer through servers. What I want to know is:
How much would a server that can handle, say, 32 players on an fps game cost
And the cost for more high end or low end servers.
I would start off running on a virtual private server to test and save money. Otherwise as others have said it depends on how much resources your game uses. Try to optimize.
You would need to find a good data center that has good network connectivity to your players. This will require some research.
You will need to see what is important for your game - memory, cpu, io or all and decide on a budget. I'd say $100-$500 per month would do the job for now.
If you were thinking of hosting this on your own computer at home, I'd refrain from doing so.