These are the games which we'll be analysing in this investigation. You can download the entire lump of raw data in an unapologetic Microsoft Excel spreadsheet if you want detailed information about individual items, but the following pages will also guide you through the basics.
Team Fortress 2
Unfathomably changed since its release in 2007, TF2 brought in its Mann-Co store in October 2010 to offer players shortcuts to new weapons, rather than having to grind on achievement servers. TF2 is now free-to-play too, though free players can't trade items until they make a purchase.
World of Warcraft
Long after WoW’s launch in 1875 BC, microtransactions were introduced in November 2009 - much to the disappointment of many existing players. It brought in some special mounts and pets that, while doing nothing that can't already be achieved with free items, are exclusive to people that are willing to lay down more money for the game.
Lord of the Rings: Online
LOTR: Online lets you play for free without having to buy the game, but subscribing gets you immediate access to otherwise paid-for content. Some dungeons and quests will be locked off to free players, unless purchased individually as DLC. There are also larger expansions which everyone has to buy. It's quite a complex setup, really.
Battlefield Play 4 Free
Battlefield Play 4 Free is Battlefield 2 reskinned and - as the name suggests - free. While most of the weapons in the microtransaction list are available to people who don’t want to spend a penny, some aren't and have increased performance stats, giving paying players a big advantage.
Realm of the Mad God
Realm of The Mad God is an MMORPG which has always been free to play, with microtransactions in the form of things such as colours for your clothes. It's worth pointing out that permadeath affects players, so if you die then you have to re-buy everything. You can also buy pets, which don’t really do anything but they do look super cute. I mean cool, and hard.
League of Legends
A DOTA clone, League of Legends is now one of the most played online games. It’s free, but only certain heroes are available to play as each week unless you buy or earn them, at which point they can be used at any point. You can also buy skins for your heroes, if you'd rather they were a different colour.
Brought in with EVE's recent Incara update, these are all cosmetic items for the new in-game avatars and, bloody hell, they are expensive. They are technically available for free for a substantial amount of in-game currency - 'substantial' as in that some are the same price as huge space ships.
Together these seven games contain over 805 individual items that can be bought through microtransactions - and the number is growing on an almost daily basis. This figure doesn't include black market items, such as those that may be traded through unofficial channels, nor does it include larger expansion packs that might be available through retail or digital distribution channels.