Okay, so maybe there's more than one way to learn Ruby. I'm going to list a bunch of different sources that exist (free and paid) to help you get started on your path towards learning Ruby.
One thing that you might ask yourself is: "Should I learn Ruby or just learn Rails?"
Good question. The answer is: "It's up to you." You can choose to know how Ruby truly works, and then move on to Rails, or you can simply learn how to use the Framework known as Ruby on Rails. The choice is yours.
I prefer to learn from the ground up, so I chose to learn Ruby first. With that being said, let's get discuss some free sites that will teach you Ruby.
TryRuby.org - TryRuby is an excellent, hands-on, basic tutorial. It's interactive and allows you to learn by not only reading about how Ruby works, but also by memory training when you actually type in the code you're asked to type in. It's basically a game that allows you write code and to learn at your own pace, without having to install any software. This is how I first got started with Ruby. I highly encourage you to check it out.
RubyMonk.com - RubyMonk is a much more in-depth version of TryRuby. I actually learned a lot about Ruby in a short amount of time. I'm surprised that there's not more people talking about this site. It's really awesome. You will learn a lot about the built-in functions that Ruby provides. Take your time and take notes with this site, as you will learn a lot very quickly.
Official Ruby Quickstart Guide - This is pretty cool, although this is where you will now have to start working with Ruby on your own machine. Not that there's anything wrong with that, as you'll obviously have to start some time. It's just much easier learning the basics on other sites. Still, now is a good time to go ahead and start getting your hands dirty.
RubyLearning.com - I'll admit, I only used this site for a short amount of time. Not because it wasn't good, but just because I had went from RubyMonk to a paid course that I'll discuss shortly (Udemy.com's Ruby Programming for Beginners by Huw Collingbourne). But the interactive courses above may not be for some people who like to just dig in and get their hands dirty right from the start.
At this point you should definitely be learning quite a bit about Ruby. I think this is important before you start looking into Rails or anything else.
As for Paid Courses, I highly recommend the Ruby Programming for Beginners by Huw Collingbourne on udemy.com. Now I actually got this course for half price after I saw it on AppSumo.com (great site with great deals!).
This course (by Huw Collingbourne) has a great book that taught me a lot very quickly. It's called The Little Book of Ruby and I believe it's free (do a google search). The book is just a quick starter tutorial before you really get into the meat of the course, but it was very well put together, in my opinion.
As for paid books, I recommend 2 (I haven't finished them, but I have read through parts and found them to be helpful):
1. The Ruby Programming Language
2. Eloquent Ruby
The courses above, along with the books, are great ways to get moving towards your goals in learning Ruby. If you have any recommendations or questions, please ask below!