If you've been paying attention to the prices of film cameras at all, you will have noticed they have been sky rocketing in price. The idea of putting the words "affordable", "good", and "medium format" is nearly laughable with few exceptions.
In this video, Jess Hobbs takes us on a photo walk, equipped with her Mamiya M645 1000s and some Fomapan 100 — an affordable black and white film. I don't personally have any experience with the Mamiya 45mm f/2.8, however, it's been on my radar for quite a while. By the end of the video, after seeing Hobbs's results, I feel inspired to go back and look at them again.
If you're just now getting into film photography or you've been doing it for a while and you're in the market for a good medium format camera, the Mamiya 645 system is a terrific choice. Though I own a different model, I have had my own Mamiya 645 for years (you can find a review here) and I love it. In fact, I've had mine long enough that I'll build out my lens collection to just about everything they made longer than 55mm. The best argument for getting on the older Mamiya models, specifically the M645 1000s, is that the lenses all use the same mounts so the selection of lenses is quite vast and comparably still affordable relative to other brands.