Spark monitors?

Currently I am using my iphone 6s plus with my spark controller and it is fine, however I would like to use a dedicated device just for the drone. I am thinking either a refurbished mini tablet or phone with 6" screen either ios or android type. There are few around $150ish. Any suggestions would be appreciated.
Thanks
Trikky

Or one of these:

It would be hard to pick just one since there are so many mobile devices that’ll work.

Thanks for advice, I will purchase an Ipad mini 4 tablet to mount on my controller.
Eyes getting older so bigger screen will be good.
Cheers
Trikky