If you run into me on the street, I'll sell you a copy for $3 (or give it to you for free if you're hard up).
I can order books directly from the publisher for $2.17 each. Shipping costs about $0.80 more per book, so the final cost is roughly $3 per book. It takes 10 days for the books to arrive (faster shipping is available, but it's more expensive). If you'd like me to arrange for books to be sent to you directly, email me at raphaelmatto@gmail.com.