The great thing about Coursera and edX are, the certificate is optional and auditing is free. I took courses on Algorithms by Sedgewick from Princeton, courses from MIT and Harvard, and so on without ever spending a cent. In fact, this is how I self-taught CS and programming (and eventually switched careers from law).

As far as practical skills go, a Pluralsight subscription was by far the thing that helped me the most. As long as you stay with the well-reviewed courses, the information density tends to be extremely high. It's how I learned enough about desktop GUI dev via WPF to score a volunteer 'consulting'-type gig with a nonprofit, and that combined with what I learned from there about Angular got me my first job.