What was the result of Napoleon selling Louisiana?

It was a win, win, situation for both the US and Napoleon. The US gained land for westward expansion and the Port of New Orleans and the Mississippi River, both of which were essential for commerce and growth in the midwest.

Napoleon gained the funds needed to continue his European war and also this sale was certain to be upsetting to Great Britain since it had prior claims to lands on the Pacific Coast of North America and an interest in commerce via New Orleans.