If your web site is actually a blog, check out blogads#IF($EnableExternalLinks).c#COMMENT#ENDCOMMENTom#ENDIF, which allows you to receive and review ads before they are automatically posted on your blog. Bloggers charge anywhere from $10 a week to thousands of dollars a month depending on how much traffic they get. You need to enable blogads to work on your site, which requires pasting a simple code into the template of your blog. See the blogads FAQ for more information on how to do this and how you get paid.
Also, Google AdSense#IF($EnableExternalLinks) (google.c#COMMENT#ENDCOMMENTom/adsense)#ENDIF is another service that you can use to generate ad revenue for your site. The service can automatically insert ads on any web site, but you don't have as much control over the content of the ads.