I just checked the current monthly special at my location:
Monthly Pass
Unlimited meetings each month
Automatically renews at $39.95 each month, that's $9.22 per week on average.
Includes FREE Registration
FREE eTools - Internet weight-loss companion
I personally would not buy any books right now. I'd wait for the new program which rolls out on the 29th. The book they give you for weighing in each week has a basic points list in it already, along with a slide rule for points and activity points. They will have little free booklets for tracking. And you will get your week 1 materials.

So really, you do not need to purchase anything other than your member dues or any sign-up fees if there are any.
If you do go with the monthly pass, then you just need to print out your monthly pass this first month, and then you can present that each week you go in.