Adding tables able to calculate prices

Good day,

Helped a lot by people from this forum, here is our website:

http://www.libromania.cl

As you can see, we offer school textbooks.

Now books season is starting here, and I need to publish books lists. It is, for every school working with us, we have to publish the corresponding books that every student has to have next season, and give to the parents the individual price per book and also the total amount of money to pay.

The problem is, what happens if one person doesn't need one book, he will want to buy all books but one. Then, I need a table where the book titles and prices are, and also having a check for every item, and when one item is unchecked, the total amount of money to pay also changes accordingly.

Thanks a lot!!!