The SAT is a standardized test owned and developed by the College Board for undergraduate admissions in US universities. It is administered by ETS on behalf of College Board. The test is designed to check if a student has the aptitude required for admissions and scholarships in the US universities. SAT gives an idea of how much have you learned from your high school and how well prepared are you for your higher education. The SAT takes more than just memorizing of word meanings and formulas; it is more about the intuition you have, how well have you been educated and how well can you think and make best choices using right information.
Often, students have a misconception that the SAT is required only for receiving a scholarship or higher scholarship; however, they miss the fact that SAT is principally a requirement for admissions into good universities. Restating the fact, even if you are not looking for scholarships, you are highly recommended to take the test since it is an admission requirement for most of the good schools.