Minecraft servers don't tend to run well on a pi, as the memory requirements for the server are pretty big.
From what I've seen it can handle a small handful fairly well, but yea I doubt it will handle 8+ on a large map to well. Looks like you can get servers hosted elsewhere for less than 5 bucks too.
For $5 per month you can sign up for any number of VPS's and simply run the minecraft server application on that. Performance is extremely good for around 20-30 people at the same time on the cheapest plans.
Why would someone spend $13 a month for a server that only allows 10 simultaneous players?
A friend of mine uses a $10 per month VPS for feed the beast (50 person) and a 32 person teamspeak server at the same time.
Is this $13 for the server or $13/month for each player? I'd imagine that it the server hosting fee which is a bit high though not terrible. If it's per player then that is atrocious.
Its $13 for the server per month. I think the main thing here is reliabilty; the server should always be up, and the fact that it is run by mojang, so support should be high.