Grand Theft Auto V's multiplayer mode GTA Online is free, but Rockstar offers optional microtransactions for players who want to speed up their progress. It turns out those microtransactions are proving wildly popular, reportedly generating half a billion dollars.

As part of former Rockstar North president Leslie Benzies' $150 million lawsuit against Take-Two, it's been revealed that GTA Online has generated "at least" $500 million in revenue from microtransactions.

To put that number into context, Halo 5's microtransactions brought in at least $1.5 million.

"GTA Online has the potential to achieve the greatest profit margin of any game created in the GTA franchise," reads a line from the lawsuit. This is in part because GTA Online's microtransactions have "nearly 100 percent profit margin," except for development costs and fees collected by storefronts.

Take-Two CEO Strauss Zelnick said in November 2015 that more than 8 million people were playing GTA Online every week. He has also described GTA Online as "the gift that keeps on giving" as it relates to the money it makes from microtransactions.

As for the game itself, GTA V has shipped 60 million copies, according to the latest numbers from Take-Two. The lawsuit estimates revenue from the game alone to be in the area of $3 billion.

Single-player DLC for GTA V is still under consideration, but these incredible numbers for GTA Online may explain why Rockstar might not be rushing to get it out the door anytime soon.

Rockstar has kept GTA Online fresh since launch, constantly adding new content including more modes, items, weapons, and cars, among other things. Just today, April 12, Rockstar introduced a new mode called Inch By Inch and the Vapid Minivan.