Stack Overflow has reams of bad advice for Objective C. The dominant suggestions (that I encounter, anyway) routinely come up at the next-year's WWDC as things

Stack Overflow has reams of bad advice for Objective C. The dominant suggestions (that I encounter, anyway) routinely come up at the next-year's WWDC as things you should not ever do for any reason (and then they continue to be the dominant suggestion for another year). Not that there isn't a lot of good, free resources out there. Apple's documentation being the most important and valuable example. But someone has to fill in the gaps, and I will happily argue that it can be worth quite a lot of time and money to learn something correctly rather than waste many hours due to bad advice. I haven't looked through these in particular, but yes, people pay for things like this, and they can definitely be worth it.