I was looking for a Sitar, it was really expensive.
Anyway, if you’re looking into beginner music theory, musictheory.net is a good place to start.
The moment I understand how to do all the diatonic seventh chords of a key, how to construct scales & chords, and how it ties to modes, it makes a lot of thing easier to process. E.g. knowing what notes / chords to play when you’re in certain key.
It’s even easier when applied to guitar, since I can learn D minor 7 in one shape, and I can use the same shape for all other minor 7 chords (in the same inversion).
I have a hard time finding free piano sheet music, so I mostly use MusicNotes, which is not free, and the viewer is really not good. For guitar, maybe spend some money on Guitar Pro, and go to ultimate-guitar.com to find tabs to download.
To delve more about piano chords, I use Chordie App, but if you’re just venturing out, I don’t think you should get it yet.
I dunno why I misread that as Sex Bot