most popular bike in greece by far… my parents had a c50 and would take my brother and I on the back… no lids no nothing. We didn’t know any better at the time 
personally I have a thing for them though I would go for the ones made pre 1990s (could be a bit earlier) where they had the rounded headlight. Those are the classics 
C50, C70,…all great.
Please don’t do stupid stuff to them, I’ve seen some mint condition ones go on autotrader for a couple of grand!!!