Classically, you should start with at least 3 discs. A putter, an approach disc, and a driver. Starting with slower speed discs and working your way up to faster speeds is recommended.  Putters are designed to be easy to throw at slow speed and have a blunt edge which doesn't get destroyed hitting the chains. The approach disc is used when the range is too far to put, but you still may hit the chains. It is controllable for these longer distances. The driver will take advantage of aerodynamic lift to achieve very long throws. Normally, your first discs are inexpensive plastics as when your technique improves, you may find you need different discs than the ones you started with.