All depends on how many people you want playing too, you need a half way decent pc that you can dedicate to the server. The server should have somewhere around at least 6 gigs of ram and the ability to run ramdisk along with a good strong internet connection, Upload should be at least 10 Mb/s and that holds only about 20 players without any of them getting chunk/block lag. Its fairly rare to see many self hosted servers as most internet providers wont give residential service costumers a high upload connection. Most people that want to run a server with the ability to let more ppl than their own friends connect usually end up renting a dedicated server
Oh that should be pretty simple to achieve then, you can either forward some ports. Give your pc a static ip and give out your ip to your friends. Or you could go the semi lazy route and just use hamachi
Btw i have made a server on Terraria is it anything like it?
Full vanilla
So thats about 5 people I want to play with.