As an affiliate you will earn 20% commission on all recurring subscriptions revenue of the customers that have signed up via your referrer code. As KPI Dashboard and KPI Project are the first 30 days free, you will start to earn commission once your referred customers are still active customers after this first 30 days (i.e. at the first billing cycle). For referrals of KPI Benchmark you will receive an immediate commission as KPI Benchmark does not have a free period.

It is up to your efforts how much you can earn in total. The more referrals you provide us, the more likely you are to earn substantial amounts of money. 

So if you bring a 1,000 customers on board that pay on average 100 USD a month,
you are making 20,000 USD a month.