In the Campaign Edit page you will be having the Field to get the Bidding Rate Information, Advertiser can set the revenue then and there he need to change.

Based on the campaign price the client sets, the weight of the campaign will be changed and it will be effected in live with in one hour.

The Advertiser has to Bid more price to increase his Campaign Weight.

Suppose, you want normal billing system then you can refer below products.

 Billing System Integration and Billing Module