https://funnyplaying.com/products/fpgbc-kit?variant=40858870284349This is a build it yourself Gameboy Color FPGA device. $70 for the parts but another $10 for the shell custom fit for the device and another $5 for buttons and membranes.
If you do go for the Analog Pocket (which they just announced all preorders have been fulfilled and they are now shipping within 24 hours.) Be aware that sleep mode and save states on the Gen III games can lead to data loss.