Dmytro Shteflyuk

Ad Rotator is a simple WordPress widget to display random HTML code 
from a given group of HTML-chunks separated with <code></code> 
on sidebar. Basically it shows different HTML every time you requesting 
page. There are infinite number of instances of this widget may exist.
<h4>Support</h4>
If you have any suggestions, found a bug, or just wanted to say “thank 
you”,– feel free to email me <a href="mailto:kpumuk@kpumuk.info" rel="nofollow ugc">kpumuk@kpumuk.info</a>. 
Promise, I will answer every email I received.
If you want to contribute your code, see the Development section under 
the Other Notes tab.
<h4>Migrating from AdRotator plugin</h4>
<a href="http://blog.taragana.com/index.php/archive/wordpress-plugin-adrotator-rotate-your-ads-including-adsense-dynamically/" rel="nofollow ugc">AdRotator</a> 
plugin is a simple file-based ad rotation solution. It was developed by 
Angsuman Chakraborty long time ago, but occasionally we have the same 
plugin names from WordPress’ point of view. If you are using this plugin, 
you may click upgrade link from your Plugins page and it being replaced 
with Ad Rotator widget.
So now you have two ways to solve the problem <code>'getad()' function is undefined</code>: 
1. you can download AdRotator and ignore upgrade notices, or 
2. you can upgrade your theme to use Ad Rotator Widget.
Here is how to upgrade your theme. Find all occurrences of <code>getad</code> function, 
and replace them with something like this:
<pre><code>register_sidebar(array(
 'name' => 'ad-area',
 'id' => 'ad-area',
 'before_widget' => '',
 'after_widget' => '',
 'before_title' => '',
 'after_title' => ''
));
</code></pre>
Make sure you’ve replaced <code>ad-area</code> with the name suitable for you. Also 
you can specify additional options, like <code>before_title</code> and <code>after_title</code>.
Then open the Appearence/Widgets page in Site Admin and configure 
Ad Rotator widget instances for your advertisements area. Just take into 
account, that in files for AdRotator ads are separated with new line 
character (ie each line means separate ad), but in Ad Rotator widget 
you should separate you blocks with <code></code> (so each of them 
may contain more then one line.)
Anyways, sorry for сonfusion, I did not want to сheat on you.
<h3>Development</h3>
Sources of this plugin are available both in SVN and Git:
<ul>
<li><a href="http://svn.wp-plugins.org/ad-rotator/" rel="nofollow ugc">WordPress SVN repository</a></li>
<li><a href="http://github.com/kpumuk/ad-rotator/" rel="nofollow ugc">GitHub</a></li>
</ul>
Feel free to check them out, make your changes and send me patches. 
Promise, I will apply every patch (of course, if they add a value to the 
product). Email for patches, suggestions, or bug reports: 
<a href="mailto:kpumuk@kpumuk.info" rel="nofollow ugc">kpumuk@kpumuk.info</a>.

Ad Rotator

Ad Rotator is a simple widget to display random HTML code (advertisements) from a given group of HTML-chunks on sidebar.

Marcin Pietrzak

Simple Classifieds lets you quickly add a basic classifieds section to your WordPress site. Designed for simplicity and speed, it provides a clean and intuitive interface for both site owners and users.
Features: 
* Effortless setup—install and activate in seconds 
* User-friendly dashboard for managing ads 
* Lightweight and fast—no unnecessary bloat 
* Custom post type for organized ad management 
* Translation ready for multilingual sites 
* Developer-friendly with clean code and hooks
Perfect for small businesses, clubs, schools, or community sites that want to offer a simple buy/sell/trade area.

Ad Rotator vs Simple Classifieds