Which iPhone model before iPhone 13 is better

My advice........do NOT buy a used phone from anyone unless you personally know them, and they have agreed to let you return the phone for a full refund if you are not satisfied.

I would consider a refurbished iPhone 12 Pro if Apple has the version/color that you want. Advantages....the phone will come with a new battery and a new warranty.

Refurbished iPhone - iPhone 12 - iPhone 12 Pro - iPhone 12 Pro Max - Apple

Do NOT buy a used iphone from anyone you do not trust.

The All Too Common SAD Reality of Buying … - Apple Community

Without knowing anything about you, your budget or what you need, that's an almost impossible question to answer.

Personally, I wouldn't buy anything earlier than an iPhone 12 just because any phone older than that isn't going to support many more updates in iOS.

If cost is an issue, I'd think about buying new and look at the current iPhone SE. You might also want to look at Apple's own refurbished store.

But, most importantly, read this:

The All Too Common SAD Reality of Buying … - Apple Community

I could be mistaken, but I think any iPhone earlier than a 12-series one will not have the radio hardware and software to support 5G cellular service. If that matters to you.

Only you can answer that question. The answer will depend on your needs and priorities.

For me, the iPhone 4S is the best model iPhone. It is the last model that was not comically large. But it cannot run any recent apps. Later models evolved into undersized tablets.

If what you are looking for is a small phone, I believe that there were iPhone 12 minis and iPhone 13 minis.

I don’t think Apple sells new iPhone 13 minis any more, but they might have Certified Refurbished ones from time to time.