GTA Online, as you might guess from the title, places quite a bit of emphasis on cars. They're level up rewards, many are expensive, they're the focus of DLC, and so on. While only relevant for single player, the modding scene is dominated by vehicle mods and skins.
What makes buying these cars particularly great for players is the ability to customize the rides with various parts, as well as alter the style and colors. While the customization options found in the game are numerous, they are limited and the players — as always — want more.
French GTA V fan RealityDesign has mocked up a proposal for a community powered emblem and livery marketplace to be added to GTA Online, which he has demonstrated in two videos. Granted, the videos are in French, but the images tell the tale well enough.
The system would involve a new emblem and skin editor within the game. Using it players could create their own designs and then sell them for in-game currency (or even real money) as a new way of collecting cash.
The creator has expressed that if this were to ever become reality, he'd intend it as an official feature included in an update or DLC instead of a mod. As we all know that mods in GTA Online gets you banned from the game. Not to mention that the entire thing wouldn't even function on a conceptual level due to the networking and files involved unless literally every player in the game has said mod downloaded.