So the base subscription is free? And they're just paying when new leads are generated? From the payment provider's point of view, you essentially have a free

So the base subscription is free? And they're just paying when new leads are generated? From the payment provider's point of view, you essentially have a free subscription with misc charges each month. So using Stripe, you would just sign up a user to your subscription plan which would have a $0 cost. Then at the end of the month when you're reconciling the billing, you create a charge on each customer equal to NEW_LEAD_COST * COUNT