<p>Princeton Review’s really awesome, but it’s better for reviewing than teaching. </p>
<p>I suggest to go to a used book store and find a really cheap general chemistry textbook. Since basic chemistry hasn’t changed much (or at all) in the past 10 years, so an old book can still be really useful. I bought one and it was only a dollar. It helps you to understand the things that your textbook doesn’t explain well.</p>