From time to time you need an ads section to your website, or maybe a client is asking you to design him classifieds area, here are the top available Plugins And Themes:

Another Wordpress Classifieds Plugin

This plugin is designed to allow you to add a classifieds ad section to your blog. You can use it to add pretty much any type of classified ads service that can run under a simplified structure taking some basic information from the user.

DEMO

Classipress

Instantly turn your WordPress blog into a professional Classified Ads Web site.
ClassiPress was built with a focus on simplicity, affordability and usability.

DEMO

wpclassifieds

wpClassifieds is a free Wordpress theme that transform your wordpress blog into a classified ads site similar to Craigslist or OLX based on classifieds ads system Open Classifieds. It is released under a GPL license.
Some features: Publish ads without registration, Publish ads with pictures, Confirm new ads by email, Edit ads after publish, Unlimited categories and subcategories, Translatable theme, reCaptcha, Akismet

DEMO