1)YouTube - Watching tutorials or useful videos may help you to improve your knowledge.
2)Hubspot courses - Buy some courses and start watching it.Choose a course which will help you.
3)TEDx talks - By seeing the TedX talks we come to know about various problems they face in starting of their career,how they deal with it ,it may be any field and we may take care that this doesn't happen with us..
Instead of wasting time on social media apps one can sign in to the above three best academies and start doing self improvement.
7)Website blogs - Even website blogs are freely available we can make use of it without paying for it any.