Photography is fun.
Sometimes, cameras get in the way.
If you choose a major brand, you’ll be able to get lenses and accsy’s for it. If no where else, eBay. But, I don’t recommend going to old for a beginner. Some cameras are hard to find extras for, and some batteries are gone forever.
Cartoon, the K-1000 is a god among cameras. So is the Canon FTB.
Some well known brands: Nikon, Pentax, Canon, Olympus, Minolta (The Top 5), also Yashica, Fuji, Ricoh, Chinon, Contax, Leica, Konica, Mamiya. I used to say that where you lived determined whether you should a ‘minor’ brand camera, but with eBay…
Just jump in and start shooting. (And build a pinhole camera, sometime, somewhere…)