We have the NFPA 70, aka the National Electric Code, which is free to access as long as you sign up for an NFPA account and allow their email spam. A physical copy of the book is about $50, not terrible.
California has their Title 24 Part 3 (California Electric Code) readily available online for free, no account needed. Want a printed copy? $200, loose leaf. Granted, loose leaf let's you swap the pages as they're updated in the interim years (the code cycle is every 3 years), but $200 is ridiculous.
The reason I bring this up is inspections. An inspector is not going to sit there while you Google a particular code to prove them wrong, especially when half the results are from forums of people debating the code. But an inspector will sometimes change their tune when you grab the official code book, flip to the relevant code (thank the maker for reference tabs), and point it out along with conditions and exceptions. I've had inspectors reconsider a field ruling explicitly because I had my code book with me (and was able to efficiently navigate to the relevant section). Problem here is that since the code is updated every 3 years, the CA code lags the NEC by 2 years, and our jurisdiction uses the most recent publication, this cycle gets expensive quickly. While it's a seemingly trivial amount when your business is off and running, it's yet another expense that makes starting a business tricky.