PU PE ??? Educate me on scopes for Mosins please

I'm starting to slip into another area of interest and getting a much better appreciation for the Mosins. Recently I bought one at auction that just shoots and operates beautifully. I paid less than I've paid for some old beater .22's! Anyway, here is my question. If I wanted to add a scope to one of these, I keep seeing references to PU and PE and there's been a "reproduction" scope and mount on the classifieds for $395 for a few days that is tempting me. I'm having a hard time justifying that much for a scope to put on a rifle that I paid 80 bucks for.

I know the originals are very expensive, just wondering about the aftermarket or reproduction scopes and mounts. Seems like a good way to make a fun rifle much better. My eyesight in the last few years is making it tougher to see open sights.