Hi Zee,
The I17 with the aluminum mast is not being sold anymore I think. The "F17" has a taller carbon mast and is cheaper than an A3. I think that the F17 would be a better class to get into since it isn't an arms race like the A class is. You won't have to worry about having the latest boat since it is a 1 design(manufacturer) class. Also, the addition of a spinnaker will double your fun especially in light air.
Dave