Welcome to Android Central! You can find a used/refurbished Pixel 3a for <$125 these days. It'll receive regular monthly updates until 5/2022 (which means it'll get Android 12), and its battery life should be quite good (unless the previous owner abused the battery).
If you want a bigger screen, you can look for the 3a XL, but that will probably be more like $150 used/refurbished.