<p>My opinion: don't bother with anything but TCB's official materials. If you subscribe to the online course($60), you get access to explanations for all the questions in the blue book.</p>
<p>if you buy from amazon (not amazon users) its ALL brand NEW!
and its still cheaper tahn the stores
i think $15 on amazon new
and $19.99 in the book stores</p>
<p>You'd have to ask the people selling the used ones if they're marked up. They should already have that noted in the description, though. But you can email the sellers, same as on Ebay.</p>
<p>98jhfg is right. You just have to pay attention to the book's condition, which should be listed by the used book seller (either on Amazon or somewhere else). If you want to buy the book used, you should click around a bunch of used book sites until you find someone listing a used book that specifically says "no writing" or something like that. A book listed in "like new" condition should probably not have writing in it, either.</p>