Microtransactions in Halo 5: Guardians are proving popular. Microsoft has announced that, in the week since launch on October 27, sales of Halo 5's REQ bundles have generated more than $500,000.

As announced previously, these funds will be added to the Halo World Championship prize pool, bringing its new total prize purse to $1.5 million. Preliminary tournaments for the event start this winter.

Revenue from Halo 5's microtransactions is likely even higher than $500,000. That's because only a "portion" of REQ bundle sales went to the Halo World Championship. However, the exact percentage split between funds that Microsoft keeps and money that goes to the Halo World Championship is unavailable.

In Halo 5, you can spend real-world money to buy various REQ packs that come with items for the game's multiplayer modes. Microtransaction pricing ranges from $2-$25. These can also be unlocked through regular gameplay.

GameSpot recently spoke with 343 design director Kevin Franklin about Halo 5's microtransactions, who stressed that they are entirely optional.

"Everything you can get in the REQ system, you can earn whether you spend money or not," he said. "There's no crazy special items that are only going to be reserved for people who spend a lot more money. Also, you get a lot of rewards whether you're playing Arena or Warzone, so you're always going to have a ton of stuff that you'll be able to use.

"The biggest thing for us the moment we started even talking about this system was that the game has to be balanced. At the end of the day, it's a multiplayer game. It's not a spend-more-to-win game. We wanted to make sure that if you spend a whole ton of money, and you thought you could get five scorpions just because you spent more money, it's not going to work. You're still going to have to earn the right to call these scorpions into the battlefield."

Microtransaction systems in AAA games are nothing new. Recent examples of games that offer microtransactions include Metal Gear Solid V: The Phantom Pain, Assassin's Creed Syndicate, and Destiny. In fact, it is rare for such games not to have them, as is the case with Star Wars Battlefront and Need for Speed.

Halo 5 generated more than $400 million in its first week, setting a new franchise record. For more, check out GameSpot's review and what other critics are saying.