The SAT and ACT are quintessential parts of the college application process and it's important to know the nature of both to choose the test that's best for you. Below is a comparative chart of the two tests and some other notable information.
*Tests critical thinking skills, not specific scientific knowledge
There are tons of test prep resources available online, including practice tests and testing tips by the official college board. Below is a collection of links to some helpful and informative test prep supplies.
Official SAT Practice Test (College Board, 2015)
Official ACT Practice Test (2015-2016)
5 official ACT practice tests (PDFs)
Some book companies to check out, all within a $15-30: