I built and run http://bots4.net. It's made a little over $40k since opening in 2011.
bots4 is a freemium text/browser-based robot fighting game. It was making $3,000/month at one point, but revenue has dropped significantly since then (and it fluctuates a lot based on the activity of whales). Operating cost is $25/month for Linode VPS hosting. Here's the revenue history as of August 2013:
It makes money purely through in-game purchases. Players can buy what are known as "stars" for $10 USD each. Stars let you order items for your bot so that you don't have to camp for them. The alternative if you don't have stars is to wait for your item to appear, so stars ultimately don't enable you to do anything you couldn't do without them, but they are a big convenience, especially in late game where certain items appear very infrequently (still only O(hours) though).
If you want more info, you can read through my posts here (linked to archived version because it's not loading on the original domain):
bots4 is a freemium text/browser-based robot fighting game. It was making $3,000/month at one point, but revenue has dropped significantly since then (and it fluctuates a lot based on the activity of whales). Operating cost is $25/month for Linode VPS hosting. Here's the revenue history as of August 2013:
http://i.imgur.com/rqcxQgv.png
It makes money purely through in-game purchases. Players can buy what are known as "stars" for $10 USD each. Stars let you order items for your bot so that you don't have to camp for them. The alternative if you don't have stars is to wait for your item to appear, so stars ultimately don't enable you to do anything you couldn't do without them, but they are a big convenience, especially in late game where certain items appear very infrequently (still only O(hours) though).
If you want more info, you can read through my posts here (linked to archived version because it's not loading on the original domain):
https://web.archive.org/web/20140210074542/http://community....