They're under $3 on Alibaba.
https://www.alibaba.com/product-detail/SAEF-2-13-Inch-High-R...
That's in the sizes used for price tags, and it's just the panel without the drive circuit, let alone a battery optimized one.
Exactly. Even OLED displays around the same size come to half the price with the driver board and a i2c interface.
This is a relatively recent price drop though, right? There was a patent that ran out recently or something?