Each affiliate program comes with a certain minimum payout or payment threshold. Any merchant will find it difficult to pay out each small affiliate commission due to transaction charges. As such, they choose to set a minimum payment threshold, and the larger it is, the longer it will take you to receive your first payment.
When considering whether the program's payment threshold is acceptable to you, keep in mind the value of the commissions offered. If you choose to join one of the best paying affiliate programs like Round Sky, you will be able to reach the payment threshold quickly, because lead prices are up to $250 per lead, and the commission threshold to get paid is just $50.