Every single game has to make money. No game can be 100% free because then there would be no money to pay the Devs, the shareholder, the electric bills, the internet bills, the costs of the servers, etc.
There are three general revenue models for videogames:
1. Box only: this is generally only for single player games that have a multiplayer component and is quite rare to be the payment model for Massively Multiplayer Online Games, which is what MW Online is. The only MMOG that I'm aware of that uses this model is Guild Wars and even that has the NCSoft cash shop.
2. Box + Monthly subscription: this is the classic MMO revenue model. People buy the box which helps offset the the production costs and then they pay a subscription. With enough players the subscriptions cover the daily operating costs, and generate profit, hopefully enough profit to invest into make expansions so you can keep your players coming back and staying subscribed. With the sheer number of games available this model is becoming less competitive as people choose not to play your game because the can't afford the sub since the money is going to a competitor of yours.
3. Free to Play: There are actually two different kinds of F2P models, the straight F2P where everything has to be bought through the cash shop, and the hybrid that allows people to subscribe for a fixed monthly sum and get the content free plus an allowance to spend on things like extra skins. If a person doesn't care about the extras he/she doesn't have to pay any money, if he/she likes the extras then they spend the money. Games like this also usually sell xp/money buffs that increase the rate of experience/money gain. F2P games usually have a way to earn cash shop credit through game actions. LotRO gives you Turbine Points for completing "deeds," WoT gives clans that hold territory a gold allowance per territory held per day which the clan can then dole out to its players to buy the gold shells, (incidentally gold shells are rarely used out of clan wars for this reason, its too expensive to waste in a public match). Lastly Star Trek Online has an exchange where you can trade an ingame resource for Cryptic Points. Because these games offer ways to earn store credit in game and they make it so that any store purchases that enhance a players capabilities don't affect general game play they don't turn into "pay to win." This model is becoming increasing popular because it encourages people to try your game, and buy the parts of it they feel is worth spending money on, rather than forcing them to pay first and then make the decision if it was worth their money or not.
F2P games have a cost to the player, however this cost is optional and if you wind up spending more money than you would on a monthly sub its your own fault. The main problem is that people have this misconception that "Fee to Play" means "Everything is Free" which isn't true, only the gameplay is free.
As for speculation on what kinds of things we might expect in a cash shop look here