Pipe chooses you. You'll know.
Some will say "Just get a 7 dollar cob." Some will say "Get a nice briar." But you'll see a shape you like.
I'd say a good first pipe would be like a 30, 40, 50 dollar briar. Medico, Kaywoodie, Dr. Grabow, Yello-Bole, Crown (when P & C has them in stock), Molina...