Some of the best affiliate marketers in the world are making millions every year. It all depends on your audience size, the price of the product you're promoting and the commission rate you make from that product. After 1 year I was making €500 a month. I saw potential and invested some more time. Now I'm earning on average over €2,000 per month from affiliate marketing. That's small fry compared to most in the industry but for me that's a lot of money and I'm glad I started. Not every month is the same. Some months you can earn a huge amount of commissions if you're in something seasonal. An example of seasonal products might be trampolines. Your affiliate sales will be much higher in the summer compared to the winter months. One friend of mine has a Christmas Gifts affiliate site and he earns 90% of his affiliate income in November / December. Seasonality is something you need to learn about before deciding on a product.