What’s the exact process for pricing a freelance service based on ROI instead of effort?

[Btaliat]

A freelancer should make sure that he considers many aspects and factors together before arriving at a particular price. You don't need to consider your efforts alone. The money spent on promoting yourself, the money that it will cost you taking the jobs and other contingent money should be added together before a freelancer should arrive at how much to charge the clients. Do you consider all these before charging your clients as freelancers?