Depends on how your sponsors pays. For example if you use something like FastClick, Burstmedia and you earn through CPM (Cost per thousand) rate. So, say 1000 people surfed two of your pages. Which is 2000 page views. And say FastClick pays $30 per 1000 views. So, you get $60 right away
. And you know its very possible that people surf atleast 5 web-pages in any websites.
But if you use Google those who pay by CPC (Cost per Click) then you might earn less. Because out of 1000 people may be 100 people could click on your ads
.