I would not recommend anything in the Amazon ecosystem if you'd like broad cross-functionality. The cover charge is cheap, but that's because the advertising and intense focus on Amazon-facing applications is the subsidy. With some effort, you can force Google Play on an Amazon tablet, but with apparently varying degrees of success. You can also side-load apps, but you don't get the benefit of app updates that way (because they're not connected to Google Play). We have two Amazon tablets at the house, and I would not buy another one.
You can't even use the YouTube app. Amazon doesn't have it in their app store. What they have allowed is an "app" that is basically a link to a mobile-optimized version of the YouTube website.
I'd focus your search on one of the "mainline" brands (Samsung, LG, Motorola/Lenovo, etc). It'll have decent hardware and will be fully compatible with anything created for Android.