I COMBINE SHIPPING - Simply add books to your cart and send a request to combine shipping prior to checking out (you may have to do it from a desktop computer since smartphone/tablets to not have that feature). Otherwise, you can always pay for shipping and I will refund you once I process the order.
Domestic Economy Shipping price table:
1 book - 5.99
2-5 books - 7.99
6-13 books - 9.99
13 & up - 14.99