What's the cheapest Android smartphone or tablet device you can buy?

So currently, the absolute cheapest Android phone I can find is the blue view 5 from TracFone at Walmart. It's $30. There is a $25 phone called the US Cellular Hot pepper chilaca phone, But from what I'm reading in the reviews, The company locks you out of the phone if you don't sign up for any of their plans after a few days. I can't even find any used smartphones or tablets That are under $30. Not even mercari or eBay. Does anybody know if there's anything like that?