It’s unfortunately more or less impossible to get an original GDEMU because the creator makes (or made) such small batches and didn’t believe in preorders or wait lists, so the only way to get one is to buy a clone on AliExpress or eBay.

I would love to support the original creator and not buy clones, but after years of waiting I gave up and so did everyone else I know. Luckily the quality of the clones is great and they work just as well as the original (some early models had compatibility issues with a very small number of games but that’s long since been resolved).

For BBA’s the only way to get one is to buy used on eBay or from a Japanese auction site. They’re not cheap though, somewhere in the $100-200 range I think, but if you do a lot of DC homebrew dev they’re absolutely worth it if you can afford it.

Otherwise you can buy a serial adapter for much cheaper and use that, but the transfer speed is significantly slower.