I'd recommend removing KitAdder because it ruins your essentials configuration file, I'm no expert with prison servers but i believe you should get some sort of crate plugin (i would recommend a premium one from http://www.spigotmc.org/) if not get something like crates pluss.
PermissionsEx is good for prefixes and permissions but if you're looking for an easier approach i'd recommend Group Manager simply because it's not as complex.
You can checkout Glaxy Node i'd recommend atleast 1Gb of ram, this hosting is easy to use lag free and has strong internet the 1GB plan is only 2.90$ approx £1.96