Many 35mm cameras are traded at very low prices, with the exception of rangefiders (Leica M are crazy high). On the other hand, medium format cameras are becoming very expensive.
Here in Europe you can easily find Om1, Om2, Om2 SP in the range 70-120 euro complete with 50mm standard lens. You can also find Leicaflex SL body only in 100-150 euro range. I have all of them.
OM1: well build, compact, shutter-mirror sweet and well dampened; only drawback the 1,35 voltage meter system; it needs an MR9 adapter to use 1,5 silver oxyde batteries commonly available.
OM2n: same quality of OM1; it works with 1,5v silver oxyde batteries; best value for money to me
OM2 Spot Program: beautiful and accurate meter system with spot reading; useful in b&w works. Mine is in pristine condition without any scratch on its delicate black paint. Drawbacks: battery drain (I need to remove batteries at the end of the day) and advance film mechanism that occasionally slips
Leicaflex SL: built like a tank; overall quality better than Olympus OM
Lens: I shot only in B&W (FP4 and Delta100) and I print in darkroom; I prefer Leitz to Zuiko in term of rendition (Zuiko contrast is harsher than Leitz); but Leitz cost 3 times Zuiko... On Zuiko side I find 100/2.8 a very interesting lens: cheap, compact, sharp with a nice bokeh, flare resistant