If you want a large quantity, about 25 can fit in Priority flat rate box costing $18.40, Ground advantage would cost $15, and the cheapest rate would be $9.50.  The activity books are sent from Pennsylvania, so these rates apply for up to zone 4, which covers 600 miles.  If you're further, then the slowest rate, $9.50 stays the same as does the quickest, flat rate priority for $18.40.  It can seem confusing, but just add to your cart and request a new total. I'll send an invoice with your choices.