There are many correct answers here, but I recommend the Pentax K1000. It is possibly the world's #1 most-manufactured camera, and was the standard camera for beginner photography classes throughout the 80s and 90s.
There are vendors on eBay that specialize in this camera and have literally 100s of cameras in stock.
Early models are all-metal, while later ones incorporate some plastic, but are consequently lighter. At this age, I wouldn't worry about the reliability difference of the two, and simply plan to replace the body if it fails.
The Pentax K-mount has a lot of cheap, good glass. The 50/1.8 is standard and fabulous, the 28/2.8 and 135/4 are also amazing and can be had for under $50.
The camera is entirely manual, with no autofocus or autoexposure available. Optionally, you can put a button cell battery in it to power a simple exposure meter, visible as a needle indicator in the viewfinder.
I've been shooting these for 40 years, so I'm a bit biased, but I do recommend them just for their ubiquity and cheap replaceability.
There are vendors on eBay that specialize in this camera and have literally 100s of cameras in stock.
Early models are all-metal, while later ones incorporate some plastic, but are consequently lighter. At this age, I wouldn't worry about the reliability difference of the two, and simply plan to replace the body if it fails.
The Pentax K-mount has a lot of cheap, good glass. The 50/1.8 is standard and fabulous, the 28/2.8 and 135/4 are also amazing and can be had for under $50.
The camera is entirely manual, with no autofocus or autoexposure available. Optionally, you can put a button cell battery in it to power a simple exposure meter, visible as a needle indicator in the viewfinder.
I've been shooting these for 40 years, so I'm a bit biased, but I do recommend them just for their ubiquity and cheap replaceability.