sparknotes AP Chem/Bio prep pack

<p>So I was at Barnes and nobles today and noticed the ap chem prep pack. I was wondering whehter any of you have used it and can comment on how it is and whether its worth it. And do any of you find sparkcharts useful?</p>

<p>Ooo.. I saw that for the History and I was so tempted to buy it. A 5 in 1 week! I'm so skeptical</p>