Seo Yoon Kim has not had a summer holiday since she was in year 10 and first set her sights on an Ivy League university.

"I just studied for the SATs [Scholastic Assessment Test] all day," said the 17-year-old, who was accepted into Cornell University last month after graduating from Manly Selective Campus.

The 3½-hour critical reading, writing and mathematics test, which Australian students have to take in addition to their year 12 exams to apply to US universities, is at the centre of a booming tutoring market for which some Sydney high schoolers are paying hefty prices.

A 28-hour course provided by SAT test preparation and admissions consulting firm Manhattan Review, which starts this Saturday, will set parents back nearly $1600, and an "all-inclusive education package" provided by Crimson Education costs more than $10,000.