Ebonite Cyclone is $79.00 and it offers some cover strength, so medium oil is OK
Stick to a price point for a beginner ball, no need to buy something expensive. The Nitrous is also a very good beginner piece. You can use really any ball for spares as long as you don't try to hook it at them. I wouldn't worry about that for now, get 1 ball and try it out, see if you have fun with it, if you do and want to get better, then maybe buy a separate spare ball.