Took the yashica to the camera store today and to my luck, I found out that it works! The battery the kooks at the other camera store sold me wasn't powerful enough or something and that's why my shutter wasn't closing. The dude there had an original mecury battery and used it to test my camera and everything was working. He told me some other batteries that worked, so I got those and now I'm in business.
I also bought a minox 35 GL for $50. Put batteries in that and the shutter doesn't work. I found a pretty detailed guide to fix it though and it looks super simple. Either way, I have 10 days to return it if it doesn't work.
AAAAND I bought a trip 35 on eBay. So now I have more cameras than I probably need but I'm super stoked.