The best Windows Tablet under $100 (in the United States) is the Double Power (DOPO) DPW10A. I'll tell you why this laptop is my choice for configuring cleanflight, betaflight, KISS, or raceflight in the field.
The DPW10A has 2 GB of RAM and 32 GB of storage, which is about the best you're going to do in this price range. What really sets it apart is the included keyboard and track-pad. It also has two full-size USB ports and a proper 12 volt DC charger. Finally, you can buy it from Wal-Mart.com, and if you don't like it, you can actually return it to your local store. You won't get that with Banggood or GearBest.