To clarify: no matter what you are, F2P Premium VIP or Lifer, you need to buy four zones in order to play them. Those zones are Moria (Mines of Moria), Mirkwood (Siege of Mirkwood), Dunland/Gap of Rohan (Rise of Isengard), and East Rohan (Riders of Rohan).
All other zones are free to VIPs and Lifers (they're technically "renting" the zones with their subscription) and must be purchased by F2P or Premium in order to quest or deed there. These zones include Lothlorien, Enedwaith, Great River, and Wildermore, zones that have been released after expansions but are not directly tied to those expansions.
The only zones that are free to everyone are Ered Luin, the Shire, Bree-land, and the Lone Lands.
The upcoming expansion, Helm's Deep, will be required to play in all zones released in November, but should not be required for any other zones released at a later time. (That may change, we'll have to see.)
Steam: Sneakeh Snake[/CENTER]