There are many (free!) online resources to help study for SAT and ACT exams.  The following are a few we suggest:

KHAN ACADEMY

NUMBER2.COM

COLLEGE BOARD

ACT

For a list of schools that practice test-optional policies, visit FAIRTEST.ORG

Looking to compare test scores (New SAT vs. Old SAT vs. ACT)?  Check out TABLES 1, 2 & 7 on the College Board Concordance Tables document.