How much ram do you need for a minecraft server for 10 people?

I have a Home hosted bukkit server and use mcmyadmin and it limits you to 10 players and i have 2gb of ram right now and have 4gb installed in the computer and am using these plugins essentials, groupmanager, clear lag, ptweaks, enjin, votifier, multiverse, multiv… Portals, and multiverse inventorys