I am interested in your project. When I started looking for laptops for the schools in Zambia, I was thinking I could easily get 500 from the local Goodwill and pay for shipping to Zambia. Wrong.
One of the issues was getting permission from the Department of Commerce to ship technology out of the country. The final discussion via email with a very helpful person with the Department was, one, if we shipped any software installed on the hardware or not installed but shipped to install, we would need to pay an export fee. The second option was to ship the hardware without software and have the Zambians install with their own software, therefore we were shipping boat anchors without a boat, older used hardware without the ability to make it usable to the schools. It took me almost two months to get to the final decision.
The end result was to purchase Refurbished Dell laptops in China and ship to Kasama, Zambia. The final cost for Dell 630s’ was under $100.00 USD.
I did do some research on the Walmart Tablets. The reviews were not that good. I suggest you look at Alibaba.com. I have been looking at tablets that appear better at lower cost. If you are looking at buying in volume, the good sources will send you a sample to test.
Hope this helps,