If you read the question, you will see that the OP is looking for "Cheaper area (apartment and food - e.g.: apartment rent max. 6000 Baht per month? I know Chiang Mai is very cheap)". Please kindly advise where this is possible in Phuket😉
Nick MuayPlam Yes, what the ministry of foreign affairs writes is kind of irrelevant because contrary to visas actual immigration at the border is not part of their remit
If you get a notarized copy of your passport from your embassy, then this meets the requirements of Bangkok Bank in Bangkok, regardless of where you stay though you might not want to tell them it is a hotel
Is it actually well spent money to focus on the "three proofs"? If an immigration officer wants to deny you entry, he can do so anyway so is this not really a bit of wasted money? Just thinking out loud...