So i am wondering if there is any free website that could teach me how to play guitar, step by step, theory , practice...
Something like book Bass guitar for dummies but in type of free web edition.
IME, "best" may also depend on the "focus" of the website, e.g, TBr Nickonbass (Nick Kreswell) has a great site with tons of backing tracks to play along with: http://www.freejamtracks.com
TBr Dmanlamius (Kris Rogers) has lots of video lessons at http://learnbass.net and on Youtube. Same with MarlowDK of Youtube fame; his site is www.playbassnow.com
Also consider checking out my >500 TB links below for lots of related links (theory, sight reading, rhythm, along with equipment reviews and much more) that will keep you busy for years to come.