Long story short, I messed up and did not have a backup. Now any vendor after Trip won't sell anything but 1 item, plus they lack their barter icon.
I tried to modify the stage values and venues where some weapons would be available, giving the Mac10 some time to shine before being completely outclassed by the Colt 1911 and whatnot. Trip works mostly correctly, but Larry and other vendors don't anymore(I can still access their shops, but their selection and interface seem bugged). I've double-checked syntax and paths in the vendors file, but couldn't find anything wrong.
I've also messed around with the weapons names and stats, but I don't think that would be a problem since those aren't addressed directly in vendors.txt . Could be wrong, of course.
I've been playing around with the file a while, so I don't remember all the changes I did. So I think it would be easier to just replace it with a vanilla, unmodified vendors.txt and work from there. Which is why I'm asking for the file. Thanks for reading.