Complex sentence: The South, however, was harmed firstly by having to pay higher prices on goods the region did not produce, and secondly because reducing the importation of British goods made it difficult for the British to pay for the cotton they imported from the South.
Split into simpler sentences: The South, however, was harmed by having to pay higher prices on goods the region did not produce. By reducing the importation of British goods, it also made it difficult for the British to pay for the cotton they imported from the South.