Edison's first patent was for an "electrographic vote recorder" in 1869, at the age of 23. This device was actually a bit ahead of its time, as it was TOO efficient and preventing polls from lobbying for vote-switching, a commonly accepted practice at the time. His invention of an improved stock ticker and the sale of its patent earned him $40,000 (worth about $600,000 today). This gave him the financial freedom to explore the thousands of ideas that were churning about in his brain.
Some of Edison's most famous inventions include: the carbon transmitter (which allowed for the later invention of the telephone), the phonograph, the incandescent light bulb, the dictaphone, the mimeograph, and the kinetoscope (the precursor to our modern film projector). One of his least successful? The concrete piano.