The Open Source Cartridge Reader (OSCR) is a versatile tool designed to help preserve video game cartridges and save data. Developed by Sanni and the community, this device allows users to back up ROM files and save games from a wide range of vintage consoles.
Unfortunately not that much less expensive, each additional slot maybe adds $1-2.5 to the project. The screen, Arduino and pcb are the bulk of the cost.
Ah that’s a shame, I guess the ones I’ve seen in the past must have been a bit simpler