If you what to learn fo free just start to code: you can start with a free course https://www.codeschool.com/courses/try-ruby https://www.codeschool.com/courses/ruby-bits https://www.codeschool.com/courses/ruby-bits-part-2 https://www.codecademy.com/tracks/ruby you can also read this tutorial http://rubylearning.com/satishtalim/tutorial.html after that you can try a game https://www.bloc.io/ruby-warrior/#/ after you learn it do some quizes in ruby http://rubyquiz.com/ finally start a project or work on opensource project
Learn how to pragmatically write and design Ruby programs in this step-by-step, project-based course https://www.codecademy.com/tracks/ruby https://pragmaticstudio.com/ruby