welp , next time i guess. Unless someone outbids me. Hope it was just bad grammar on the sellers part. shit
If you're motivated you don't need a light meter. I shot my first roll on a camera with a shoddy meter (not sure it even worked when I used it).
You can use your phone as a external meter. There are two ways, find an app which works OK, but I haven't found one I was confident in. Probably best for iPhone where devs know what to aim for (various Android phones can have differing sensors).
What I did was take a sample picture with my phone where I like the exposure and look at the exif inside photo details. You may need a third party photo app.
This is from a random picture I took, my phone is kinda worst case scenario because it uses random ass settings
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What I do is approximate. F2.8 is slightly darker than 2.6, 1/250 is slightly brighter than 1/315 so I assume it is that. We don't need super accurate numbers with print film or black and white.
If you're shooting ISO 100 film you can use f2.8+1/250, f4+1/125... If you're using ISO 200 film you can use f2.8+1/500, f4+1/250 etc...
Think of ISO 125 as pretty much ISO 100 etc. If you're uncertain err on the side of overexposure.
This takes some time, but if you're out shooting you'll get an idea like "this weather is f8+1/250" and mostly use that, maybe increase by a stop or two when shooting stuff in the shadows.
Edit: The OM 1 used a 1.35V mercury battery which isn't sold any longer. You can replace it with a zinc air hearing aid battery which I think needs an adapter (I'll look it up). The down side is those only last a few weeks while traditional cells last a few years. They're not that expensive tho.
Edit2: OK, the OM1 used a 625 cell, but you can get smaller 675 zinc air replacement cells that seem to work without any modifications, but you can buy adapters that go around the 675 cell. I'd find a cheap pack to test it with, maybe ask seller if he was certain it didn't work should you win.
Edit3: After a quick Google I found this. This is exactly what happened with the camera I used and would be easy to fix.
This was a wise move because it turned out the wire soldered to the battery holder was about to break (a common OM-1 affliction). After a few more rolls of film I would have had a camera with a dead meter.
Here's a YT video going through the issue and fixing it. The diode installation is for using 1.5V batteries and not necessary. I would take the bottom panel off to check if that's what's wrong. It looks very scary with all the gears, but to my knowledge it's very hard to break anything by removing that panel.
https://youtu.be/dFq9etVH2og