They need to model after Eve Online. Eve really opened their alpha (ftp) characters to do more but they can buy a lot of things from the official store for money to help out. It basically gives them a ton of fun but always leaving them wanting more and so they end up subbing. Those that don't still buy things like plex and stuff so it keeps the money train rolling. The alphas bring a lot of PvP in which keeps the Omegas (subbed players) paying and playing. It can't be too restrictive to encourage vets to return and new players to join but at the same time, it leaves your mouth watering to sub.
Oh....and good evening Chessy!