Ditto to what the others have said about the entry level balls available. You can really get a ton of ball for the money now. Some of the Roto Grip options I can think of are the Rumble and Wrecker. Storm offers the Lights Out, Frantic, and the Freak'n Frantic. These will cover the majority of your light to medium patterns.
If the house you bowl at is dryer, you could always consider the Roto Grip Scream or Shout and the Storm Tropical Breeze line.
My own experience is that the Frantic from Storm offers a lot of versatility for the price point. Even though it is primarily designed for medium-light conditions, I have been able to use it on a variety of heavier or flatter patterns as well. It's uses the R2S hybrid cover paired with the symmetrical N.O.S. core. It's a great combo that gives you easy length, a predictable backend move, and carries really well by keeping the pins low. It's a great option to consider.
