Ipad
Am I able to turn in older iPads for a credit to purchase a new one?
iPad mini, iOS 12
Am I able to turn in older iPads for a credit to purchase a new one?
iPad mini, iOS 12
You might get more for your iPad if you try and sell it yourself.
What to do before you sell, give away, or trade in your iPhone, iPad, or iPod touch - Apple Support
Ipad