Simple, but very useful and powerful plaugin, which adds to your WordPress-powered website a special widget which can show unlimited banners in any siderbar of you theme.
All you need to do is to place it in the right place, add title, URL of the banner’s image and your affiliate link.
Features:
<ul>
<li>Unlimited banners to any sidebar of your website;</li>
<li>Show up any .jpg, animated .gif or transparent .png image;</li>
<li>Customize the width of every banner with ‘width’ parameter. No need to fill in the height.</li>
</ul>
Ownyourblog Banner Widget is bulletproof solution tested on many blogs.

Ownyourblog Banner Widget

Simple, but powerful widget to show any banner you want in your sidebar. One-click solution!

darrinb

The Easy Banners Widget is an easy-to-use widget that allows you to configure and display call-to-action banners in your site’s sidebars.
Preview your color selections before saving.
Features
<ul>
<li>Configurable widget title.</li>
<li>Easily select banner color using built-in color picker.</li>
<li>Include <code>html</code> in your banners message.</li>
<li>Easily select text color using built-in color picker.</li>
<li>Preview your color selections before saving!</li>
<li>Easily link banners to any url.</li>
<li>Choose the default (basic) CSS styling or roll your own.</li>
</ul>
Developer Features
This widget was built not only with end-users in mind, but also plugin developers. Almost every aspect of this widget is extensible through filters and action hooks. You can even add your own form fields to the widget form!
<ul>
<li>Need to remove a field from the widget form? Not a problem! Every field is passed through its own filter for easy customization.</li>
<li>Need to modify the output of the widget? Easy! The output is passed through numerous filters, allowing you to customize the content to meet your project’s requirements.</li>
<li>For a full list of action hooks and filters, please see the plugin documentation: http://darrinb.com/plugins/easy-banners-widget</li>
</ul>

Easy Banners Widget

Easily build call-to-action banners for your sidebars.

Ownyourblog Banner Widget vs Easy Banners Widget