IMO, its personal preference. I have about 12 discs that I use for certain shots and certain situations. Resist the temptation to try lots of different discs. Concentrate on learning to throw only one disc until you develop a feel for throwing golf discs. Some excellent disc choices for new players are: Aero, Leopard, Polecat, Cobra, Stingray, Archangel and Sidewinder.
When and if you buy online, stay the hell away from sun king discs. Long story, but they are lowlifes and you will have a hassle with them.