There are paid versions to these plugins, but the free version has also served us very well. In this tutorial to better GTmetrix score, we have used the FREE versions.
Here are other tutorials to improve your GTmetrix Score:
- To improve Add Expire Headers & Leverage browser caching: Click here
- Cache configuration as recommended by GTmetrix: Click here
- To serve Scaled Images & Optimize Images: Click here
- Loading jQuery from the Google CDN: Click here