Genuine question, I was interested in trying to play around with one a while ago, and I spent a fair amount of time searching and could not find a single monitor for under $1000, and most of them were in the $3000 to even $7000(!!!) range for a device that can literally only display a single line of text at a time.
If there are manufacturers making cheaper devices, or even just doing anything interesting with the hardware like building multiple-row 2D displays instead of 1D single-line outputs, I would love to know about them. It's a market I'm somewhat interested in.
The cheapest option I ever found was https://www.boundlessat.com/Blindness/Braille-Displays/Brail..., which is $1000 for a device that can display a whopping 14 characters at a time.