This is a bit old school but hey, it's free and it still works.
Send us your banner image(s) and the URL link and we will place you in the rotation.
We just need 2 pieces of information.
1.) The URL where you want us to link you image to....
2.) The image to use.
Rectangle ads like the ones you see on the site. 468x60 OR 728x90 are best.
Typical Banner Sizes