I spent about $85 (AUD) on mine, it's a 5.83-inch tri-color (black/white/red), 648x480 display. For that much it came with the interface board so I could wire the display to my microcontroller easily enough.
I think that's reasonable cost-wise for my purposes (I'm making a status display to go inside my white-build gaming 'rig' to look shiny). Red takes about 12 seconds to refresh, AFAICT I should be able to get sub-1s black updates. You can get 7-color versions for about the same price but the refresh on those is very slow.
As ever it depends what you want to do - If you want a 2-inch tri-color display, in a format where you can attach SPI wires easily, you might get away with $20 AUD. You can find small greyscale eink displays very cheap (sub-$1) like this - https://www.aliexpress.com/item/1005003555154992.html
But you'll need to find some sort of interface from the ribbon cable to whatever wires you need.
If you want full-color, fast-update e-ink/epaper, that's just filtering into the market AFAICT, and it's much more pricey. I can find a 31.5 inch full-color epaper display for about $2200(US)!
I think that's reasonable cost-wise for my purposes (I'm making a status display to go inside my white-build gaming 'rig' to look shiny). Red takes about 12 seconds to refresh, AFAICT I should be able to get sub-1s black updates. You can get 7-color versions for about the same price but the refresh on those is very slow.
As ever it depends what you want to do - If you want a 2-inch tri-color display, in a format where you can attach SPI wires easily, you might get away with $20 AUD. You can find small greyscale eink displays very cheap (sub-$1) like this - https://www.aliexpress.com/item/1005003555154992.html
But you'll need to find some sort of interface from the ribbon cable to whatever wires you need.
If you want full-color, fast-update e-ink/epaper, that's just filtering into the market AFAICT, and it's much more pricey. I can find a 31.5 inch full-color epaper display for about $2200(US)!
(There's a video of it in action here - https://www.youtube.com/watch?v=bPnJh4QcjDY)