Since buying and using turkey calls is so much fun, you should try at least two types.
Buy a box, Lynch makes some good production ones, and a slate type call. K&H Ol' Yeller is a good one is Primos Ol' Glory or any number of others.
Pick up one double reed diaphragm call to try and learn on.
Toss in a copy of the tape "So You Want to Be a Turkey Hunter?", hang around here a lot and you will be pretty well prepared to start turkey hunting.