You can make your own free banner(s) with this site and get the html code so you can display your ad on other websites.
Fotor is another banner maker that will allow you to create your banners in different sizes for free.
ClassifiedAds.com is very similar to Craigslist.org - it's basically free to use. And you are free to post your banner or ad, the potential buyer can even contact you for free.
With The Banner Exchange you can place their code on your site and it will automacally display other members' banners, which in return, you are earning impressions yourself, meaning you ad is also being shown on other websites. Win - win situation.
Banner Advertising
Online banner ads can help generate a nice percentage of the revenue for product or service. When done right, advertising with banners can be a very effective way to reach your target market. We're sure you know by now that reaching the correct target audience can be critical to the success of your business. Below are some resources that will help you get started with banner advertisement.