Inexpensive? No. But you're basically describing Sony's DPT-RP1:
https://www.sony.com/electronics/digital-paper-notepads/dpt-...
https://www.theverge.com/circuitbreaker/2017/4/10/15242238/s...
It's $700. Also, it can take input from a stylus to annotate the documents on it. But otherwise it's what you want. I, too, wish there were cheaper options for this purpose - even if it was a thick, heavy monitor with a stand and built-in 120V power supply rather than a tablet (though I suppose the power characteristics of e-ink displays mean that the economics will typically prefer the tablet form-factor). Reading is just a lot more pleasant on an e-ink display.