How much did the US pay for the Mexican Cession?

The United States had originally offered $30 million for the Mexican Cession. But Mexico refused. That angered the Americans. When the American army crossed the Nueces River, the Mexican army shot at the American army. That started the Mexican War. After the Mexican War, they signed the Treaty of Guadalupe Hidalgo. The treaty said that the Mexico had to cede the Mexican Cession and the United States had to give Mexico $15 million.