The SoS articles are a great bang for the buck. Older articles may be read without a subscription, and there are enough of them to keep you occupied for months. I read Mr. Senior's book and was not impressed (although I like his articles and the SoS podcast). I guess because the title promised that some "secrets" would be revealed, but there were none.
YouTube is a treasure-trove of information, if you have the patience to sift through all the crap, e.g. teenage "producers" showing off their subwoofers. Start with
Pensado's Place, which is perhaps not exactly at a beginner's level but certainly easy-to-intermediate. There's also the
Recording Revolution YouTube channel, which is more basic and geared squarely at the beginner.
If you walk, exercise or ride the bus/train every day, listen to some podcasts. Check out
The Home Recording Show, which ranges from simple introductory concepts to more advanced techniques. They've produced over 200 episodes over the past 5 years, each a little under an hour in length, so there's plenty of content there to keep you entertained for many hours. This is my favorite companion for my daily walking regimen.
That's just one of many audio-related podcasts out there.
Sonic Talk is another one I enjoy, although despite being conducted by audio professionals, the audio quality is very bad. That's because they all hook up via Skype. It's like hanging out with a bunch of serious audio heavyweights on a conference call while they shoot the breeze. The conversations are only loosely structured and often take off in unexpected directions, which is why I enjoy it.