[1] https://support.apple.com/guide/iphone/supported-models-iphe...
I run iOS 14 on it.
Cost me about $100.
This also makes me wonder what the price dropoff across models is compared to the worldwide average. Is every model "oh wow" more expensive, or is there a gradient upward trend that tapers off the closer you get toward the iPhone 13 end?
A random Android phone? Could be slow after 2 years, could be without software updates, could be filled with bloatware of a network provider that isn't actually yours. Could be you buy it and you'll need a different phone 6 months later. And even within the same model, there are huge differences. E.g. Samsung galaxy phones can have different processors inside, and varying amounts of bloatware installed.
iPhones are just a safer choice. Therefore higher worth
The cheapest second-hand iPhone that runs the latest iOS 15.0+ is an iPhone SE 1st gen (2016). Current prices on eBay indicate a price of $70.
There is not a single Android that has been supported for this long of a time.