BUT, DO NOT WORRY.
Here I will provide you some resources that will help you with the complete course of JEE and NEET subjects free of cost with standard quality even better than many paid courses. These resources will be different from most of the widely available courses in the sense that these will be without any excessive promotion between lectures. Just learning, pure plain and standard.
1. Dakshana E-Learning program for JEE and NEET
For: JEE Main & Advanced, NEET. Separate courses for each. Separate courses for each class from IX-XIII.
Why it is good for you:
Lots of detailed lectures easy to understand, properly organized under topics. Advance Level content covered for JEE and optimum score can be achieved on the basis of NEET lectures. All the lectures are by Dakshana senior faculties and are meant for those who can not afford to coach. So, you can be assured of content quality.
Link: Click here to go to the course page. To know more about Dakshana click here.
2. Physics Galaxy
Cost: ₹0 for videos
For: JEE, NEET
Why it is good: Short videos available for topics. So, say if you want to study or clarify a particular small topic you don't need to go through the whole video, you have a special video for that.
3. Mohit Tyagi on Youtube
This channel on Youtube is a gift for those who want to study for JEE advance free of cost. Playlists for all chapters are available on this channel in a sequential manner.
Link to the channel: Mohit Tyagi
This source was suggested by Saurabh Gupta a successful aspirant of JEE.
Link: Physics Galaxy Website
If you know similar sources helpful for this topic please tell us so that we can add them here to help more people. Click here, you will be given credits for your contributions.