Online course or tutorials for Linux?

Hi everyone my name is Gustavo Woltmann and I am a worker in a publishers office. I am planning to add some skills and I am thinking of Linux. Are there any online course or tutorials offering Linux class? Do you have any idea how much does it cost?

@ gustavowoltmann -

Try here: Resources - Linux Foundation - Training

Here is a free one to get started:
Another: Free Linux Books - Download PDF | Read Online