I have taken a number of paid online courses, some of them well done (such as the some of the courses you will find at ed2go) and some of them taught me a different lesson than I expected. Aquent Gymnasium offers free online courses, focused on UI/UX, that are as well done, or better, than any of the paid courses I’ve done: http://gymnasium.aquent.com/catalog/. The course on responsive web design goes into a lot of detail, and is extremely well done. They also have offerings on jQuery, Bootstrap’s grid layout, and Node.js, amongst others. If you do well in one of their courses, you may be encouraged to consider working for them. No obligations, of course.
And finally, while more Computer Science oriented than focused on front-end development, you can find a number of free university courses online, as well: https://www.coursera.org/courses?orderby=upcoming&cats=cs-programming. Amongst these you will find courses on Android programming and Python.
And that’s what I have in my list, thus far, for material that meets the following threshold: either a book or course related to front-end development, is of high quality, and is free. If you know of additional material out there that you believe meets these bars, please do share in the comments section.