Why did the united states economy becoming much more reliant on money in the late 1800's than in previous times

The reason why the United States economy became more reliant on money in the late 1800's because of the Civil War. The U.S needed to pay for the expenses of transporting soldiers, feeding them, and etc. Going to war is not free, and it is a very hefty price when a country goes to war. Because of this, the United States started to compose what is now called "income tax." The income taxed made citizens pay to help fund the war. After the war, they also needed money to rebuild the South.

Some authors have commented about this topic that United State of America became more reliant on money in the late 1800's than in previous years because the civil war expenses.

The civil war changed things in the south more than the north. The Southern states were brought to heel and stripped of much of their prosperity.

The reason so close of this statement was  the civil war.