How to Switch from Manual to Automation testing

Hi Folks! I am currently working as a manual tester. Its been 4 years I am doing this and now I have no mood to continue as a manual tester. Can u guys suggest ke how can i change my career path from a manual to automation tester? Which course will be helpful for this? Because I tried contacting few institutions such as Crio.Do, Star Agile but the issue is they are either asking for a high course fee or their rating is very poor. Please suggest a correct way so that i can transform my career. Thanks!