It looks like Pocketbook still sells eReaders that use SD Card slots. The Pocket Touch Lux 4 sells for $120 (plus tax and shipping) from GoodEReader either directly or via Amazon. It comes with 8 GBs onboard RAM and an SD slot that goes up to 32 GBs. I don't know much about Pocketbooks, but you might go to the Pocketbook forum and ask folks what they think of this one. It has a touch screen (E-Carta 212ppi) and front light.
https://goodereader.com/blog/product...ok-touch-lux-4
or
https://www.amazon.com/PocketBook-To...gateway&sr=8-7
It looks like you can also buy them from Grooves.Land (a German online retailer that offers free shipping to the U.S.) for $119 to $122 depending on which color you choose.
https://www.grooves-inc.com/advanced...book+touch+lux
Pocketbook's home page for this model.
https://www.pocketbook-int.com/us/pr...ok-touch-lux-4