You are comparing living in the one of the most expensive cities in the world to someone living in Zimbabwe as if they are remotely the same thing. Only 40% of Zimbabwean people have access to toilets, what do you think that number is in London?
Yes, that was my point, they aren't the same thing at all. It's complete bullshit to say that it costs pretty much the same to live in a tin shack everywhere, as it clearly doesn't.
Your minimum is probably a well, septic tank, permits and so on, this is if you even get planning permission. It's almost certainly going to be cheaper to buy an old terraced house in a post industrial town.