How much did the Louisiana Purchase cost?

The answer is: $15 million. Imagine buying what was, at the time, enough land to double the size of the U.S for what people pay for a single mansion today (or a single-room apartment in New York). As good a deal as this was, Thomas Jefferson didn’t exactly negotiate in the kindest way. Owned by France at the time, he threatened to partner up with Britain against Napoleon if he wouldn’t accept the deal. The French, as they do, instantly surrendered.Source