Is this a good deal? (Mamaiya C330)?

Hmmm...the C-330 is my favorite work horse camera of all time. I bought mine used with two lenses for $350 USD in 1979. (Still have it, too!)Personally, looking on Ebay I think can get you a better price. Chances are high that the light seals will need to be replaced. Not expensive, but should be considered as an addition to the cost.