To order 2 books: $31.91 [$28.00 + $3.91 shipping]
To order 3 books: $45.91 [$42.00 + $3.91 shipping]
To order 4 books: $60.32 [$56.00 + $4.32 shipping]
To order 5 books: $74.32 [$70.00 + $4.32 shipping]
To order 6 books: $88.73 [$84.00 + $4.73 shipping]
To order 7 books: $103.14 [$98.00 + $5.14 shipping]