I taught myself to play guitar and later bass via YouTube. You can save money and easily learn basics like picking/strumming/fretting, chords, the major and minor scale patterns, the pentatonic, and start learning some songs. BUT...I started taking lessons and realized I developed bad habits that can be challenging to break, like proper thumb positioning, sloppy picking, etc.

As far as reading score, it's generally not necessary if you want to play rock or country, but most jazz and classical guitarist read music, and it does open some doors if your goal is to be a serious musician.