The one this website is using for now is Project Wonderful. It is an international advertising website that requires almost no real computer skills to use. Basically if you have word processing and Paint skills you can work their system. They offer a full range of price options from the free (which does take its tole in time and attention) to a few hundred dollars a day. As one might expect the "free" websites have lower traffic but only using them I am garnering up to forty clicks a day to my site that I would otherwise never see.
If you want to see how it works just turn off add block for this site. ( I PROMISE there are only classy adds from PW. And what you find on the google boxes is really up to you.) There is a PW add on the home page and one on the blog page.