It depends on your product/service and your targeted market, is it possible to make a such contract as "pay per sale", at least in initial phase.
I manage multiple FB ads accounts, and all my clients have coFlere
I can help you in facebook advertise , run your campaign manage your PPC at just 15 USD. complete like, share, followers post views etc, i can give you 100% real and genuine user can help you to reduce your overall biuFlere
Facebook advertising expert here. I will setup your campaigns to get maximum ROI.
I have over 5 years of experience in Digital Marketing.
I'd love to hear more details about your project.