Acer Iconia One 7 B1 780 is the latest tablet by Acer that retails for under 100 dollars / pounds. This Acer B1-780 specs include 7 inch IPS display with 16:9 screen ratio, 1280 x 720 pixel resolution, MediaTek MT8163 quad core processor that runs at 1.3GHz, 1GB RAM and 8 / 16GB of flash storage. You would be able to expand the internal storage using micro SD card slot.
The back of the Acer B1-780 is home to 2MP main camera and 0.3MP front camera. Its inbuilt battery will give you around 6 hours of continuous runtime and runs android 6 marshmallow operating system. Expect some children related software to come pre loaded on it.
MediaTek MT8163 is a great processor packing more than enough power to runs android marshmallow OS but as expected in these cheap tablet, the only thing not so pleasant would be its display which has poor viewing angles and average touch sensitivity.
Acer B1-780 price in UK is said to be 79.99 pounds which is about 105 euros/dollars.