It's not for people who can afford a laptop/desktop, also know about the existence of Hackernews and know enough English to comment on it.
It's also not supposed to be available in retail market and will be directly provided to Government Universities, Colleges, Schools. I already know about a pilot project in National Capital Region(Delhi) as my cousins have registered for it.
Any keyboard will work with it. An Intex keyboard costs 3$ and Microsoft costs 20$. Leather/Synthetic case will be again for 4-10$.