At 200$, the vintage ones may be lighter than new ones in that price range. Go for steel, it is proven to last; look for double butted tubing. Prices about right for an overheated used bike market, like NYC. Prices vary wildly on the kind of moderate-low level bike you're looking at depending on your location.
__________________
"It's always darkest right before it goes completely black"
Waste your money!
Buy my comic book!