I have a question I'd like to ask before purchasing a new iPhone that involves advice about switching carriers, carrier reception, if in my circumstances I should be going through a physical store or online and through the carrier or Apple, and buyback or exchange programs. Is this ok? Would parts be ok to ask individually? Do I need to make sure they're broad enough to not apply only to me? What's acceptable for what I want to ask?
The main limit on what you can ask for this is making the question ask for answers that are opinion based or you ask too broad a question (see the help centre especially here)
You need to ask about one thing at a time and make it so that any answer is based on facts and not opinion. I don't think there is a problem if the question only applies to you but iy must be for a given reason.
I would not that mobile phone contracts are complex and subject to change at any time so I would suspect the cheapest way will change and is unanswerable.
I would hesitate to ask those sort of questions, they seem overly localised, very much point in time, and potentially of little re-use for future visitors.