I have to disagree, or at least add a strong caveat, concerning Kindle tablets for kids. Their parental safety controls are abysmal and very easy to get past for a child who wants to. Or for a child to break through accidentally if they don't even know what they're doing. That also includes the ability to purchase things without permission. It should also be noted that, last time I checked, apps purchased through their store are generally disabled unless you are currently online,and you can't add Android games that you've already purchased elsewhere. Then, if they stop carrying an app that you have purchased, or change it to a monthly subscription, your copy stops working. stops working.
Kindle is still a pretty good deal, though, if you're an adult and plan to use it for movies and shopping, and maybe some free games. Aside from their tech policies, they are fairly well built and easy to use.