Overall, the cost of the war was significantly higher for the South than for the North, due to several reasons.
First of all, it was the South that relied the most on slavery. As slavery was outlawed, the South had a shortage of labor.
Another reason is the fact that the North had industries that allowed them to be more effective during the war and to continue to be functional afterwards. On the other hand, the South relied on agriculture, which was difficult to conduct while the war was going on.
Moreover, after the war ended, many former slaves migrated to the South in order to try to find better opportunities. This meant that the population in the South decreased, leading to a shortage of workers.
Finally, the South was also deeply affected in terms of their pride and identity, which had important consequences in social and political terms.