You might look at this one: https://www.amazon.com/TCL-Unlocked-Display-Version-Smartphone/dp/B0B1DFJGSX

$85 right now: Factory unlocked, I believe certified for use on all 3 networks. (so if Tello doesn't work out, you'll have options.) Shipped by Amazon, sold direct from TCL.

I'm currently using the slightly older, slightly smaller, A30. It's pretty decent for a cheap phone: my biggest complaint is it doesn't get quite bright enough for outdoors in direct sunlight, and it's a little hard to find cases/screen protectors for it.