Sm64ex-coop is amazing! I never got far in super mario 64, the camera gave me headaches. I did know it was a revolutionary game for it's time though.
With sm64ex-coop, you can enable free look with the camera, and if you set it up right it feels just like the camera in many modern games. There are hi-res texture packs (Render96) available that also look amazing. And finally, they added a bunch of mods and features, one major one being the ability to play multiplayer.
Oh yeah, and it's cross-platform, runs on a whole bunch of different devices. I highly recommend checking it out, it's sooo much better than anything you'll get from an emulator.
If the game is out of print, buying a used copy, even at scalper prices, isn't going to benefit the original devs or even the publishing company at all. They won't see a penny of that money.
In my particular situation, my son has an OLED Nintendo Switch and a fairly big, growing library of games for it. Nintendo is already getting plenty of my money. They're not losing any significant amount of money over my fullsets of NES, SNES, and N64 ROMs, the vast majority of which are not available on Switch Online / Virtual Console.
Pokémon. You get to choose from Charmander, Bulbasaur, and Squirtle for your starter. And everyone you know will judge you for which starter you picked.