The main thing to keep in mind is that your page will quickly be deleted if you post nothing but links trying to make cash. People will start reporting you and someone in charge will flip the kill switch.
The best technique is to post random stuff related to the page a couple times a day, then once or twice a week (say, Tuesdays and Fridays) make a money post.
Seriously, if you're only making $20 per update you're selling yourself short. Sign up with the right CPA networks and carefully spread your updates out while growing your fan base, and you could easily rake in a couple thousand bucks a week. Anybody trying to pay you $20 to post -their- CPA link on your mega-page is taking advantage of you. They give you $20, they make $500...wouldn't you rather be the one to make that $500?