After years of seeing many ideas for affordable braille displays completely fail, it looks like there's [actually going to be one on the market soon.]
(http://www.aph.org/research/orbit-reader-20-details/) The CNIB is already taking [pre-orders]
(https://shop.cnib.ca/ProductDetail/tec9999999999_deposit-for-orbit-braille-reader-20) at a retail price of $499, and we're expected to be getting them before the end of 2016.
20 cells of braille for $499, with a bluetooth connection as well as SD card slot. It doesn't have all of the features of a "premium" braille display, but at 1/4th of the cost of a standalone display that seems pretty reasonable.
It's even better when comparing to a braille notetaker (which range from $2000-$4000 for a current model device around 20 cells.) Most people who would buy one already own a phone or tablet that can be used with a braille display. If you didn't, $400 for an ipad plus $500 for an orbit reader would get you a full-featured system that would regularly be updated and include all the apps you want.
There are other ways to buy (or get) a braille display affordably, but it's pretty awesome to be able to point to this thing and say "hey, there's a brand new braille display you can buy for yourself for about the same cost as an ipad."
I think I'll be ordering my own once they're here in the US!