I would buy that HP Chromebook x2 that I mentioned above. You can get it on Amazon for under $500.
I use mine as a tablet 100% of the time. I replaced my Samsung S2 tablet with it. It does more than a normal Samsung tablet… It is like a full Chromebook. I like that it uses the full chrome browser. A normal android tablet uses the android version of Chrome, which has some limitations.
Plus, you get a full detachable keyboard included in the price. You have it in reserve, just in case you ever want it… You do not have to buy it separate. It also comes with a stylus, but I have never even opened mine.
Just be aware that it is a 12 inch tablet. If you want smaller, then look at one of the Samsung Tab A models. But, it can use most of the Android apps.
I think the S4 tab, S5 tab or S6 tabs may be above your price point.