Hi,
So, as the person above said, they were invented in the late 1880's (1886 and in Germany according to Wikipedia). But, when I studied American History at GCSE, one of the key developments in car manufacturing was the invention of the Model T Car by Ford, the first car really designed for the wider consumer.
What with the recent introduction of the assembly line, which enabled the quick production of the Model T, this car may actually mark the first invented car which was really used for the common man.