Reddit mentions of The Musician's Guide to Theory and Analysis (The Musician's Guide Series)

You can usually get older editions of those books for significantly cheaper. That would be my recommendation. Those books are really the ones that are vetted, tried and true.

2nd edition Aldwell/Schachter for $15

1st edition Clendinning/Marvin for $10

There's only one edition of the Laitz, I think, so if you wanted that one you'd just have to bite the bullet.

In no particular order:

• I'd suggest getting into a good, thick theory book, like this one. It may seem boring at first, but I can guarantee that classical theory will serve you no matter what genre of music you are creating.
  
• Better tools do not make you a better musician or composer. Skilled people can do a surprising things with cheap or free instruments and software.
  
• Never stop creating. You're starting from the bottom and the only way is up. You will not become a worse musician, practice will only make you better.
  
• Regarding synthesizers, I would strongly suggest staying away from presets. Learn how the synthesizer works and don't rely on pre-made patches that came with it.
  

I really do like Laitz, but the book can be pretty dense, especially if you're trying to teach yourself. Clendenning and Marvin's book takes a lot of Laitz's approaches but is a bit more accessible, in my opinion.