My budget SLR (film!) recommendations

#5 Zenit 12xp

The Zenit 12XP (or similar ones like the uglier 122) was one of the first old SLRs I aquired simply because like everyone else I wanted a Helios lens, and a few of the cheapest ones came attached to their camera counterparts (attic finds). It's the last place on my recommended list, because it's certainly useable, looks quite cool and is the natural fit to a Helios lens. However, I found it too clunky as a daily driver, it's fairly limited in shutter speeds, more than once I wasted frames because it's taking a while getting used to find the right amount of pressure to the shutter button to trigger the lightmeter without actually taking a photo. All in all, you get style points for using it but it's not the most intuitive SLR. Maybe still the best option to get a Helios lens, but seeing how much the prices for those increased on ebay over the past years I even doubt it's so easy to find this couple anymore. In that case, see #3. I paid below €30 in 2014 to give you an idea. Back to M42 lenses further down the list.

BTW, I'm super bored of Helioses now. :)

#4 Fujica (STX-1, Porst and in X-mount general)

This is more a mount than a camera recommendation. In my experience the Fujica X mount cameras are among the cheapest options you can find, simply because they're somewhat forgotten. Usually the recommended budget mounts are M42 and Pentax K, they are widely available, there are huge amounts of cheap 3rd party lenses and you can find everything from low to excellent quality. As for Fujica X, that mount is far more obscure nowadays, first it never was as popular, but also maybe because the lenses are not as easily adaptable due to a longer flange distance than the other two (too long for a Canon EOS adapter ring in particular). That said, there are adapters for mirrorless, but we're not talking about that now. The point is, Fujifilm has always made excellent lenses and this is a dirt cheap way to get an analogue system with quality glass. The pictured STX-1 is the lowest in the line, dead simple and all manual without any fancy extras like LEDs or automodes. Quite comparable to a Pentax K1000, just with a more limited minimum shutter speed of 1/700. I have some of the more advanced models like the AX-1/3/5 which come with more fanciness and auto modes comparable to the 80s Canons - and I like those too, however I had issues with light leaks and the sealings/mirror dampening dissolving and smearing across the screen, so those might need a bit more work.
Now the Protip - Fujicas were often rebranded, here in Germany you can find them as Porst CR1-CR7 for even less and far easier than with the original Fujica label. Check the usual suspects in your country (Sears? Hanimex? etc.) if they had those too. Again, back in 2015 or so I bought a few and never paid more than €30, sometimes including the lenses.

#3 (and1!) Praktica MTL5b

You could put that on the top of the list too, as a general recommendation it actually belongs there, just that I have two personal favorites occupying that space.

This for me is the ideal budget camera for old lenses, it's probably still the cheapest system you can find, and at least in Germany and Europe you still find them everywhere on flea markets or dirt cheap on ebay - it was after all THE East German camera, rarely anything else there.
But the main point is, it's also good. In my experience those Prakticas are among the most reliable cameras I ever touched, dead simple but built to last. There's a lot of prejudice towards "commie cameras", but in this case it's unjustified, during the 60s the East German camera industry was among the world leaders and very innovative - btw, they were the ones who introduced the M42 mount, not Pentax - but Pentax was inspired by them. As we all know they went downhill just like pretty much everything in the GDR with the end of the Ulbricht era, but that doesn't mean the cameras weren't of good quality anymore - they just lost the innovation race and kept building the same base models for decades, mostly for export
For me, the MTL5b is the absolute sweet spot, dead simple, reliable, easy to learn and use and it uses a single modern LR44 battery. There are a few similar models like the MTL3, Super TL500 and 1000, all of them not shabby, but using slightly harder to find batteries or such.
Prakticas can often be found rebranded in the west, I think Sears had them, Revue in West Germany had almost nothing else, but I prefer the look of the original GDR models and there shouldn't be much of a price difference anyway.
Ideally you get the camera with it's usual kit lens attached to it ( as pictured), which is a very attractive lens also ideal for adapting to digital and chances are high it's the only 50mm you'll ever want. Most of the Pentacon lenses are either Zeiss or Meyer-Görlitz lenses, sometimes on the earlier Prakticas you still find them with the original label. The 50mm f2.8 is iirc the Meyer-Görlitz design with with the famous "soap bubble bokeh", I personally don't like that effect and much prefer the f1.8.

#2 Porst Compact Reflex (Cosina CSM)

This one marks the end for my personal search for the ideal, everyday M42 camera, one of my 2 most used systems. It's inspired by #1 on the list. All I wanted was a small and absolutely easy to use camera that I can throw into my bag wherever I go. The Porst (Cosina) is one of the later M42 cameras from the time when smaller SLRs came into fashion, which I highly appreciate - it's basically the same size as my favourite digital camera body, the Fuji X-E series. One other feature I like was the light meter/stop down mechnism being coupled to the shutter button, it's all right below your fingertip, but not as clunky and prone for accident as in the Zenit 12xp. Other than that, it's simply the sleek look, light weight and general fun to use this little guy, there's nothing really special about it other than that. Ah yeah, of course it was cheap. :)

#1: And the winner is... Pentax ME

Yes, that's right... no MX, no "Super" nothing fancy, just... tiny and cute and lovely. Well, the story is... I always liked my K1000, but I wanted it smaller. I wanted a Pentax MX since I thought I needed all the manual settings, but damn the MX got expensive on ebay. So I looked for other Pentax bodies with the small form factor and found out nobody wants the ME because of the missing shutter speed selection. Makes sense I thought, maybe the ME Super would be... but compared to the MX the ME Super looked unintuitive and was in the same price range, and then there was that one ebay auction for a ME body and 12 rolls of film... which apparently nobody had seen but me, because I got it for the €25 starting price. 

Suffice to say, I never looked back, otherwise this wouldn't be my #1 camera, would it? This is my most used film camera, an everyday snapshot camera that doesn't have to do any fancier job than just work out there, and it does so beautifully, looks adorable and weighs nothing.
Of course, there is a busload of awesome and totally different Pentax cameras to recommend, the whole Pentax K system is a great start to get into film photography, I think next to M42 it's the widest adopted mount with third party cameras and lenses everywhere. Original Pentax glass is awesome, and the one pictured with the camera my absolute recommendation, it's for sure the sharpest 50mm I own, even wide open. I never looked at 1.4 lenses on ebay, they are always overpriced, and seriously, what difference is there between 1.7 and 1.4 that justifies quadrupling the price? That said, even the good old Pentax 50mm f2.0 is a great lens, just stop chasing those overpriced fast lenses!
Anyway, what a wonderful time it was when full frame cameras were this small and pretty. And when Pentax still made pretty cameras...