I don’t have too major of a collection as far as quality, but I have been holding on to all my old Nintendo games and consoles since I first got them back with the OG game boy and NES, and I occasionally expand it when I find other old games I like when I have the money and can find them out in the wild. I have most of the consoles except for the more obscure old handhelds. (Still working on getting an original game boy advance to fill out the collection, but they are fairly expensive considering the costs of the later SP variant, which I have floating around.
Yeah, the prices some of these older consoles go for are just insane. Most first-party GameCube games, for instance, are really overpriced nowadays, let alone the more obscure acccessories (Wavebird, component cables etc.).
I'd love to have a GameBoy Micro but I probably don't have to tell you why I'm most likely never gonna get one... The SPs can be pretty expensive too if you want one with a backlit screen (AGS-101).