neoslab

Powered Minifier allow you to reduce your page load and increase your performance by minifying your HTML source along with all the CSS and JS code present in your markup.
<h3>License</h3>
Good news, this plugin is free for everyone! Since it’s released under the GPL, you can use it free of charge on your personal or commercial site.

Powered Minifier

Honestly it's the best minifier plugin for Wordpress 

Simply Excellent

Reduce your page load by minifying your HTML source along with all the CSS and JS code present in your markup.

Alessandro Carbone

How many times have you wished to minify in a clean way all the stylesheets and scripts of a WordPress website?
AssetsMinify takes every CSS and JS asset included using <code>wp_enqueue_style()</code> and <code>wp_enqueue_script()</code>, merges and minifies them.
You can also use AssetsMinify to create your WP theme using Compass / Sass / Less without configuring any <code>config.rb</code> or that kind of stuff.
AssetsMinify is based on Assetic library.
<a href="https://github.com/acarbone/AssetsMinify" rel="nofollow ugc">Fork me on Github</a>.

AssetsMinify

Use Compass, Sass, Less, Stylus, CoffeeScript (and more ...) to develop your themes and minify your stylesheets and JavaScript.

Powered Minifier vs AssetsMinify