You could earn $10-20/month in IRON by putting your computer to work.
The amount of IRON a user can earn will depend on your computer's video card, the time your PC is mining, and the algorithms.
Using boosts, obtained from challenge rewards, cores, and other promotions, also increase your chances of mining more IRON for a certain amount of time.
In addition to the IRON earned from mining, you will find Mining Bonuses from time to time, which will award you with additional items as you reach specific times mining milestones.
For a list of all supported cards, click here.