There is a noticeable scarcity of online textbooks specifically for high school-level Algebra 2 and trigonometry, with most available resources leaning towards Algebra 1 or college-level materials. Users have pointed out that while Wikipedia offers a Wikibook on algebra, it is incomplete and lacks a section for Algebra 2. Suggestions for studying ahead include utilizing local libraries or purchasing used textbooks from platforms like eBay or Amazon. Schaum's outlines are recommended as affordable review materials that provide numerous worked examples and exercises. The discussion highlights that the abundance of college-level resources may stem from the greater availability of time and support for college professors compared to high school teachers, who often juggle multiple classes and larger student numbers. Overall, while online resources for high school math are limited, there are alternative avenues for obtaining study materials.