I have a situation where I am to bill the site users monthly. But the invoice amount that is raised depends on the the leads that our site generates for his business. For example if the user gets 5 leads from my site and I charge him $10 per lead, at the end of month he will be charged $50. similarly leads might vary each month so will the amount.
Now I cant store his cc/ paypal credentials on my site for security reasons nor can I pre bill him or ask him to take credits and then use it. Please let me know the way to handle this situation. How can I handle this using paypal?