Is a 50 f1.8 sharp? I highly doubt so.
Yes it's good as a starter lens and it's cheap. But if you want a sharp picture from it, you'll have to stop down to around f8 or so. Then what's the point in having f1.8?
The D70s was not designed with a vertical grip. 3rd party grips are available. But they don't work well.
A 18-70 is good lens. In fact, I believe it's the best kit lens from Nikon. Like yyD70S has said, 2nd 18-70 is now selling for around $200-250. But sometimes you might find some copies below $200 ;p Just keep your eyes peeled.
The 18-70 comes with front and back caps and also lens hood, and lens manual. Take note of such things, because you don't want to be short changed. Check the lens electronic contact plates. If they are lose or dirty, the lens might not work when mounted, or it can be problematic in the future.