There is no limit to the amount you can earn in Fast2SMS affiliates. You will get 30% commission on the first transaction done by your referred user.
The maximum limit of commission which you can earn from a single refer user is 3000.
Example: If you share your Affiliate refer link with 100 people from which 40 people signs up at Fast2SMS and each 40 person adds 2000 in their Fast2SMS wallet, then you will get 30% commission on each user’s first transaction. So, the total amount which you will receive is 600 (30% of 2000) * 40 = 24000