I want to make a server, but I would like to build before I make the server public. Can I do that on a preexisting single player world, or do I have to start with a paid-for server?
I only have experience with CraftBukkit server that I set up for kids at home. There, you can just supply a single player save game as starting point of a server. I suppose you can do the same with paid server hosting.
Yes. Most server hosting sites will let you upload your pre-existing single player world or transfer your world from another site.
Ask me about our Bedrock Minecraft Realm - New Caledonia and our Java Towny, McMMO and more RPG Server Hy-Brasil.