There's been a recent trend towards free to play games; however, they seem to be anything but free. The top 10 grossing games in the Google App Store are all this sort of "free". However, this concept isn't even new. Arcade games have been designed to extract quarters from unsuspecting people for decades. Some games have you pay to play, while most modern games have you paying for in-game items. Here's a round up of tricks game companies use to slowly bleed your wallet.
Pay To PlayIn a pay to play setup, which include most arcade games and a handful of free-to-play (F2P) games, you pay a small amount to start playing and set you up to pay another small amount to keep playing. The original arcade games were difficult but fair and a masterful player could play forever on a single quarter. Modern games, however, set you up to die an unavoidable death but make you feel like you could have avoided it with some skill. That way you rationalize every quarter as being for practice.
The Slow Bleed
The earliest arcade hit that I'm aware of in this category is Gauntlet. A quarter buys you roughly 1000 health and it slowly drains over time. Getting hit by a monster (unskilled play) drains it even faster. There are items such as food to get health back but over all even a skilled player will have to drop in another quarter eventually. Games like the Simpsons Arcade Game took this to the next level. It replaced the slow drain with unavoidable attacks which make the slow drain less obvious.
Tough Sections That Are Just Tollbooths
Side scrolling beat-em-ups come to mind for this technique, though it's fairly wide spread. At various points along the game there are difficult sections that almost guarantee some amount of damage to the player. Unlike the bleed technique, this damage comes in bursts. When done right, this way keeps you from feeling overwhelmed and sets you up for "just one more quarter" to get through the hard part. This technique is typically implemented with periodic boss battles. This effect can be amplified via the game art. The boss will have two to five appearances, all of which look "almost dead." When the boss starts shaking and emitting smoke it feels like it will only take one more quarter to push him over the edge. I'd wager that the game can grab a quarter for every art change.
Pay for Items
This style is the most common in F2P games. The game usually is entirely free, but optional in-game items can be purchased for varying reasons. This trick is best done using an in-game currency with a weird ratio to dollars, just like purchasing stuff with foreign currency. Most people can't do the exchange rate math in their heads, and wind up paying more.
I never thought it would be possible to monetize boredom in an optional activity becuse I always figured the cure to boredom is playing a different game. Farmville, however, proves that this is not the case. Farmville uses many psychological tricks to keep you playing such as peer pressure, where your actions affect your friends, and loss aversion, where if you stop playing your farm decays destroying your hard work. But whatever the cause, once you have a player addicted to something boring, you can make them pay to make the game less boring. I hope that the recent trend in Zynga stock is a sign that people have developed some sort of immunity to this.
Pay to cheat
People hate the feeling losing and are willing to pay to avoid it. This one is probably the most aggravating to me because it can ruin an otherwise great game. I'm a big fan of Yahtzee and for a while I got hooked on Dice With Buddies. After a while, I noticed that other players were getting a lot more Yahtzees than me. As a player who's average game is within 5 points of playing perfectly, I knew something was up. Basically the game sells you extra rolls (cheats). Any sort of paid-for boost in a competitive game is not gameplay, it's cheating.
Pay to Show Off
I don't know which collectible card game invented it, but adding shiny foil versions of the regular cards was brilliant. People want to show off, but to do it right the object needs to have some universal appeal. Everyone on the planet knows that things that sparkle are 10 times better than a non-sparkling version. Team Fortress 2 is probably the king of optional accessories with their hat system. In TF2 hats serve no purpose except for looks, and yet the company has made more money on a free game with paid hats than a paid game with no hats.
Collecting the Set
People love to have a complete collection even if the last few items aren't worth having. Give away half a set, and people will pay for the rest. While lots of games offer collection, not many try to monetize it other than digital collectable card games. However, just about any game with a dollars for gold exchange will get a sales boost from people trying to buy a rare item or recipe just for the sake of having it.