Dungeons and Dragons online from Turbine is a great MMO and has a great pricing plan.

Here is how the system works:
The basic game is 100% FREE. You do not have to buy the software or pay a monthly subscription fee. You may purchase optional account options, but it is not required. Some of these options include: Additional races- Drow, Half-Elf, Half-Orc, and Warforged; Additional classes- Favored Soul and Monk; Shared character banks; Access to additional adventure areas. The core races and core classes are extremely competitive in the game, the addon races and classes are by no means necessary to play the game. Now I have heard many people complain, "I have to buy a Half-Orc, If I want to play it" or "I have to buy access to Delera's Tomb to play that adventure series". Meanwhile these people play World of Warcraft or EQII. Do the math, with these you pay $15 a month = $180 a year. You also had to pay for the original software. Yes you pay for additional quest,classes, and races but in WoW you had to buy "The Burning Crusade", "Wrath of the Lich King", and whatever other expansions come out. That is another $50 or so a year. Blizzard is pretty good about limiting expansions, but many other companies release 3-5 expansions a year.

The other common complaint is "I have to group with people to level up". I rarely have to group with other people, but I do because I am playing an MMO. Isn't playing with other people the point of a Massively Multiplayer Online game? If you want to solo, play Fallout 3, or Dragon Age. But, If you are good you can solo most questlines.

The grouping system is much more flexible compared to other games. If players are smart and play their classes well, you do not have to conform your groups to the typical Crowd Control, Tank, Healer, and DPS model that many MMO's require. The 3 roles (and keep in mind these are roles, not classes and therefore may be filled in by many classes) for DDO work like this:
Aggro management or Damage Mitigation: The basic idea is to control or spread ouot where the damage is being dealt.This role may be filled by a tank or a caster. The control wherre the mobs apply damage. A tank (fighter, paladin, Barbarian, and other classes with a nontraditional build) may fill this role by having a high armor class and/or lots of hit points and the use of the intimidate skill- this makes mobs ignore the rest of the group and focus on the target they can not hit of signifigantly damage. Wizards, Clerics, Bards, Sorcerers and other caster types can fill this role a number of ways: Charm spells, Command Undead- this adds some of the enemies to your side. These are the best types of spells imo. They are really great if you wish to solo; Sleep, Hypnosis, Web, etc... these take mobs out of the fight until you wish them to engage; Summon Monsters spells- summon an monster to tank for the group. A wizard with the Pale MAster enhancment line may summon a monter and a Skeletal minion, this gives the group two more members that can absorb damage. A rogue with a high Use Magic Device skill may also fill the caster role by using wands, scrolls, and other items. Another source of damage that must be considered is traps. These are traditionallly handled by rogues, but there are creative ways to handle them. Casters may handle them by using various protection spells. Example a trap that sprays acid, can be bypassed by casting Protection from Elements- Acid. A caster may also summon a monster behind the trap and the monster will sset it off as it returns to the casters side. Tanks may handle these with their high hitponits to absorb the damage.

DPS: Plain and simple- hurt stuff bad before it can hurt you. Melee classes can continuously deal damage. In DDO, if you can not find a true tank, more DPS fills in just fine. Kill stuff faster = getting hit less.
Melee classes may accomplish this by using 2 handed weapons to deal massive damage,especially when you crit. You also attack in a broad arc which may damage multiple enemies at once. A nontraditional way for this character that I used quit effectively is the 2 handed weapon rogue. I created a dwarf using a great axe that was hiting for 20 to 75 points of damage at level 3, plus sneak attack damage.
Dual wielding, or 2 weapon fighting, to attack more often. 2 weapon fighting deals less damage per hit, but swings much faster. This is especially good becasue it allows you to hold 2 weapons. I recommend to weapons that deal different types of elemental damage, like one flaming and one corrosive. More swings= more chances to crit or produce weapon effects. This is a very common style, mostly because people think it looks cool. You do take a penalty to hit, this may be reduced by taking feats. Fighters and Rangers excell at this damage style. Many people make their rogues dual wield, but remember this is mostly cosmetic. Rangers and Fighter have a higher Base Attack Bonus and access to more feats that lower penalties for 2 weapon fighting. Be original and hit more often.

Ranged DPS- rangers and fighters may become experts at dealing damage with bows. Rogues may use bows, crossbows or thrown weapons and still get benefit from their sneak attack damage if at close range. A new favorite of mine is the rogue with a repeating crossbow, within 30 ft of the target and flanking, you produce high DPS.

Burst DPS- Castertypes (Wizards, Sorcs, Clerics, Favored Souls, and some Bard builds) may deal high amounts of damage and or Area Effect damage to quickly reduce the opposition. I do warn that caster DPS at low levels is poor nd you run out of spell points quickly, unless you have someone provide you with good gear. But around level 6 a caster such as wizard starts to get more efficient at spell point use and damage dealt per spell point spent. Taking the wizard prestige enchancement Archmage greatly increases his efficiency.

Quest Access: this is the one area that is best filled by a rogue. With their skills they can find and unlock optional objectives and extra loot in quest. Caster types may fill in this role by using spells like detect secret doors and knock. This is not a required component of any group, but it helps to get all the XP and $$ possible from a quest.

So basically in DDO any class can potentially fill any role, especially if you make use of multiclassing and enhancement lines.

The game is a pretty old game, but this new business model has brought tons of new players. So there is plenty of opportunity to group. Last time I played Warcraft, it would take me an hour to find a group and then another hour or so while we waited on the exact mix of classes needed, like finding a Preist who can actually heal.

The loot system in the game is awesome. Every chest has something in it for every player. No more running the same quest 20 times only to lose the roll or not have aenough DKP to bid on the item.

XP is not cut for running with a group. In tradtional MMO's xp is divided amongst players. More people= smaller xp return. This encourages solo grinding to gain levels. In DDO you get xp for completing objectives. More people= increased speed of completing the objectives. The XP is the same for a solo artist as it would be for a full group. Difference being is that the full group with deal with objectives faster, therefore producing increased XP returns. This encourages group play, and lets not forget what MMO means!!!

The game is very friendly to small guilds. Warcraft really requirews you to join an Uberguild to get the best experience. You also have to build your character like that uberguild wants you to or you will not have a place in groups.

Now there are a few improvements I would like to see. I feel that if you buy and adventure pack, they should implement the ability to group with players from other servers, increasing your chance for finding a group. I would aslo like to see world PvP objectives like Dark Age of Camaelot had. No other game has had a truly good PvP system and I would like to see DDO implement it.

I honestly place this as one of the greates MMO's of all time and think it is great that I do not have to pay a monthly fee.