Currently, there is no free or paid tool that can keep track of leads a vendor gets and automatically charge them. You will have to create it yourself if you have coding knowledge or hire someone with experience in tracking.

Homeadvisors between $15 to $60 per lead which is an effective way of generating revenue.
Hippages start from as little as $99/month on a 6 month contract, and don't pay any commission, ever.

I've successfully helped over 150 entrepreneurs, startups, and businesses, and I would be happy to help you. Please send me more information before scheduling a call - so I can give you maximum value for your money. Take a look at the great reviews I’ve received: https://clarity.fm/ripul.chhabra