I am looking for a freelancer who can build an Adsense site that will earn consistently $5-$10 per day at least for 21 days.
Anyone who can do that reliably will already be doing it. Why would they hire themselves out to you for you to capture the gains of their work?
They would only be willing to work for you wages is they could not be doing it reliably: so why are you hiring them?
Reminds me rather of my (oft told) story about the turning lead into gold peeps looking for investment. If you can turn lead into gold why are you looking for investment?