USC scholarships are competitive. They consider all students who apply by the deadline but they are not automatic. STAMPS is a full ride, but that is for about 5 students a year. Monk which covers about 10 students per year are full tuition + $5k - not quite full ride, but consider international students. Half tuition (200 awards) and full tuition (100 awards) are still very competitive. Some of the scholarships require interviews.
STAMPS is available at about 40 schools and some will consider international students. stampsfoundation.org for more information. You apply to the schools directly, then they consider applicants for STAMPS.