"Limitless". There are affiliate marketers who are making millions of dollars a month via affiliate marketing. I personally make more than $30000/month from Affiliate marketing. Below you could see a screenshot of my earnings from one such affiliate program: The key here is how you are approaching the whole process. Are you using a blog or using PPC to market affiliate products. The one that I have been using from the past 10 years, is via blogging. This has been the most effective one so far.