I'm searching a relatively cheap Android based E-Book Reader using E-Ink technology. The purpose of using Android is on one hand to have an open source operating system and on the other hand having the ability to expand the E-Book Reader using several third-party apps.
"Relatively cheap" means that I expect the reader to have a good functionality-price ratio, however the maximal price should not exceed 160$ (including shipping to the European Union). Refurbished and used devices (in good condition) are also an option, as long as they have a (really) good functionality-price ratio.
Possible options I could ascertain so far are Boyue, Onyx and Icarus. Unfortunately, the availability of Onyx and Icarus readers seems to be very bad. Boyue models which are in stock are T61, T62 and T63, but I'm not sure whether there are better ones on the market and which of them may fit my needs.
I'm grateful for every answer which can help me finding the right device and apologizing for the absence of activity resulting from my recent discovery of this forum.