Aren't "easy" monetization methods already built in the Steam workshop? Isn't that what Team Fortress 2 is all about for example? Steam/Valve calls that "user generated content". Larian should just be able to use the same or a similar system since they already support the Steam workshop...
There was a lengthy presentation about the topic at the latest Steam Dev Days. I can only recommend watching the video:
https://www.youtube.com/watch?v=SRyUpR4qOxU
