What determined the value of Bitcoin during its appearance is the same thing that determines it now, the interest of the people. The first record that exists is from July 2010, when Bitcoin started trading at an estimated price of $0.0008 to $0.08 per coin. What has led us to today's value, or to the previous ATH, is the interest of the people in learning about and being able to use an economy that is not in the hands of governments or banks, a free economy. An economy that we and no one else can benefit from.