A cheap Bluetooth enabled Braille display would be a good option although would only serve a small segment of the population in developing countries. For more info see

http://en.wikipedia.org/wiki/Refreshable_braille_display

All current models I have seen are over $1000, over $2000 for anything of a decent size. Something that could use Bluetooth to connect to old iPhones, low end Android devices, and windows computers running the open source screen reader NVDA could be very useful in countries where government does not subsidize the purchase of expensive assistive technology.