This depends on your annual income. Generally mechanical music IS affordable! Most beginning enthusiasts can afford a player piano, a gem roller organ, a small monkey organ, or a table top disc music box. Price is generally a function of rarity. Remember, however, that price or rarity has nothing to do with enjoying piece. An inexpensive common foot pumped player piano can give you hours of enjoyment as can a Gem roller organ that you find at an antique market. As your income progresses you can afford larger or rarer pieces of mechanical music such as coin pianos, reproducing player grand pianos, orchestrions, automata, large upright disc music boxes, violin playing machines, calliopes, etc.
