The 5 free resources to learn jQuery are as follows:
1. Learn jQuery
Official jQuery tutorial that covers everything related to the topic. It's free and constantly updated to match the latest version. The tutorial is for both entry-level and advanced-level developers. It covers everything jQuery-related and is a great reference to clear any doubts.
Created by jQuery(Official)
2. jQuery Fundamentals
jQuery Fundamentals is designed to get you comfortable working through common problems you'll be called upon to solve using jQuery. To get the most out of this site, you'll want to read the content and try the various interactive examples. Each chapter will cover a concept and give you a chance to try example code related to the concept.
Created by jQueryFundementals
3. jQuery tutorial Playlist
YouTube playlist consisting of 200 videos that cover everything jQuery-related. Each video is 5-10 minutes long and very much engaging. Everything from basics to advanced is covered in this playlist.
4. jQuery Tutorial
A well-organized tutorial that covers everything jQuery-related. Both beginners and advanced programmers can find this tutorial very well appealing. The tutorial provides code snippets, diagrams, and practice problems to understand the subject better.
Created by Tutorial Republic.
5. AJAX made easy,with jQuery
Created by TechSprout