The Cheap Hackable E-Reader That Fits in a Card: Xteink X4
The Xteink X4 is a pocket-sized ESP32-powered e-reader priced around $50–$70 that trims features (no touchscreen, no backlight) but thrives on a passionate open-hardware community. Its CrossPoint Reader firmware lets Calibre syncing, Wi‑Fi transfers, and endless tinkering, making a cheap device surprisingly capable for hackers and readers alike.