How to make a Minecraft multiplayer server for premium and free?

I bought the game "Minecraft" and I showed it to some of my friends. They can not afford to pay for the real thing as of now so they used the free version. Is it possible for me to make a server and allow them to play on it as well as me? (Recap-I paid for the full game at minecraft.net, they on the other hand can not and have the free riped version)