We will charge your credit card only after you’ve used up your free credits. For instance, if we gave you $150 in credit valid for 30 days, that sum will be applied to your charges automatically. If you only spend $50 in those 30 days, we will not charge you anything. And if your spending exceeds $150, we will only charge you the excess of that sum. Keep in mind that you have only 30 days to use your credit, after that the remaining credit will be forfeited.