And heck, if they are being cheap first and lazy second, this may help them?
Walmart's price is $5.97
Atkins.com price is something like $4.50 right now (plus shipping).

If they are serious enough to read the book, they are (sadly) not serious enough to lose the weight. The first 2 days in, I asked for borrow my mother in law's book and within 3 days, I HAD to buy my own for reading and reference. I would have read the book BEFORE I started, if I could do it over again but by day 5, I knew all there was to know for induction.

Yeah, feign ignorance and tell them they MUST get the book so they can be mentally well equiped to lose the weight forever