As much as you can.
- Setup fees, since campaigns do take some time to setup if you're thorough.
- Ongoing Management fee
- If you want to charge a % of ad spend, 15% is a common amount used.
-Pay per result :
You're getting paid for each conversion you make
I recommend charging the exact opposite. Charge as little as you can.
Yeah got your point. I didn't take time to clear my thoughts : pay per result / % budget is often possible. I agree that you should charge in a "classic" way when you can't do result/ Budget %I never do pay per conversion with a client, because I've no idea how well their site/product/service converts. I can do affiliate/revshare deals myself. Clients offer that because they have no idea how well their site converts, and want to make that your problem.
Improving site/product conversion rates is part of the expertise that clients are looking for, in my opinion. In practice it varies a lot.
Charge for your expertise, and time spent, that's how I look at it anyway.
I've found that competing purely on price turns into a race to the bottom, like a knife fight in a phone booth.