Here we are some free plugins which are helpful to getting this goal.
This is another great plugin with good performance based. It has a setting page which is suitable for both normal and advanced users. This plugin will show a good impact on loading speed of your web pages.
- It uses gzip compression to minified files.
- HTML output should be optimized
- This plugin has ability to exclude files from being minified to avoid some conflict
It is up to you and the theme you are using that which plugin you feel most suitable for your website. If you know about other good plugins please share with others in your valuable comments.