You can now buy Neotron Pico boards direct from Elecrow. See https://www.elecrow.com/neotron-pico-rev-1-1-assembled.html. I have very limited stocks, and they are priced at $99 each, for a PCB with all components fitted except the RP2040 and the CR2023 coin-cell. It's Open Source hardware and there's loads of detail on the Github page.
