I have 2B & 3A
2B - 99% new, only a few pages with pencil marks HK$110
3A - 70%new, many inside book exercise have been done, about 80 pages out of 344, HK$90
$177 x 0.9 = $160
$160 - $110 = $50
Using credit card gaining points, use an entire new book for one year just for $50 ! It is quite interesting indeed.