Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Book is OK. Spend extra $20 if you buy used book.

There is a software with the book, which has to be used for working on the problems.(The book has no use without the software).You can register the software only once.If you buy a used book, you have to pay another $20 to get a new serial # to use the software.My seller mburns1000 didn't mention about this when I bought the book and I ended up spending another $20.