There is one, it's called the Raspberry Pi ecosystem, but due to the small volume and the target audience largely being not-my-own-money (think educational institutions), the price is quite detached from the production cost.
A 4.37inch E-Paper in 3 colors is $24, problem is need you to program yourself (they have code sample in python, for raspberry pi), and you need a raspberry pi, case, cables, etc.
Also, these cheap epaper displays are, of course, of lower quality (slower, lower resolution) than an kindle display.