Mabinogi
When Korean MMO and Welsh mythology meet.
Partying up - which is absolutely necessary for most of the dungeon quests that comprise the story threads - is rather difficult to do spontaneously; your best bet is to join a friendly-looking guild, advertised by keystones placed around the inter-town roads, and use its chat-channel to find willing companions. The normal chat channels are full of spam; being free-to-play, the game's largely unmoderated
There's no obligation to pay for anything in Mabinogi - you can't buy in-game currency with real money, nor good items. What you can buy is a Premium Pack that gives you a variety of benefits, removing the experience penalty for dying, giving you extra inventory space on your person and at the in-game banks (which is pretty essential if you want to play seriously) and endowing your character with a 10 per cent experience boost. You also get presents on your character's birthday every Saturday, which sometimes come in the form of enchanted weapons. It also lets you create your own guild and open a shop to sell your own items.
You can pay real money for character cards to make new avatars, or to Rebirth your current one. Mabinogi characters age at the rate of one year a week, and after the ever-so-ancient age of 20 they barely receive any new AP points from ageing to spend on skills. New or rebirthed characters can start from anywhere between age 10 and 17, and Mabinogi's deification of youth dictates that younger is better. Younger characters gain bigger stat bonuses and more AP, so if you don't want your rate of improvement to drop off dramatically, paying for a Rebirth is pretty much necessary.
Pets also cost money - as usual, they can fight with you, or get you around faster. Mabinogi's only other form of fast travel is the Moon Gates, which appear at night and will transport you to somewhere specific. You get no say in where they go, though, so you might have to wait around for a few nights if you want to get to a particular town. It's rather like getting a bus in Eastern Europe.
Mabinogi has novelty on its side, and variety, but it's neither a beautiful game nor a particularly compelling one. Its unusual combat deserves praise for relying more on player intuition and skill than invisible dice rolls, but at heart it's all about the grind, whether you're milking cows, trying to make yourself a hat or just chipping away at the story quests. It's worth remembering that it's essentially free, though, and doesn't cripple players for declining its premium services - a fact that its very young and enthusiastic base of dedicated players seems to really appreciate.