Lineage II: Goddess of Destruction is a free to play MMORPG. While the whole story and world of the game is freely available, there are premium options available in the game's store.
The story in Lineage II: Goddess of Destruction revolves around Shilen, the goddess of the title. She has awoken and is using her dark powers to destroy the world. However, an opposing force in the shape of the last of the Giants has been released to fight back, and has made a deal with humanity to enlist their help. It's fantasy; it doesn't have to make sense!
What this all means of course is you get to choose one of 8 character classes - Yul Archer, Feoh Wizard, Iss Enchanter, Aeore Healer, Sigel Knight, Othell Rogue, Wynn Summoner, or Tyrr Warrior. You'll then be sent on a series of quests, increasing in difficulty and requiring more and more experience to survive them.
Graphically, Lineage II: Goddess of Destruction is perfectly acceptable for a modern MMORPG, and the world of Lineage provides lots of scope for exploration. Gameplay is pretty straightforward too, although
Lineage II: Goddess of Destruction isn't quite up to WoW standards, but it ticks all the MMORPG fantasy boxes, and the free model makes it really accessible.