There are thousands of websites to learn programming for free, but not all of them are good. Here I have listed some of the most popular websites to meet your requirements:
Codecademy: Learn to code
Free Online Programming Courses – Learn Programming | Alison
Introductory Programming Courses | MIT OpenCourseWare | Free
Learn C - Free Interactive C Tutorial
Udemy (not all courses are free, some of them are paid as well.)
Hack.pledge() (Community of Developers)
And, many more..