Almost everyone in the civilized world is an amateur photographer. Great photography has come from almost all walks of life, and not all of the best pieces have come from professionals--some of the greatest photographers on the planet don't get paid for their work. Still, for most of the time since cameras have been around, the majority of great photographs have come from professionals; in large part, only professionals could afford the high-end equipment necessary to handle many situations; only professionals could afford to refine their art with the constant cost of practice--for film and development never have been a cheap enterprise.
With the advent of the digital camera, photography has finally become an open source of creative fulfillment even for the non-professional. Amateur photographers need not worry about the cost of learning their art once they have purchased a single, quality digital camera.