I have a friend who would like to do WW but she has neither the time nor the money to pay so she just wants to buy some of the books and the slide calculator.

If you have a WW center near you, she could just walk in and buy the books. They ususally don't ask and never ask for proof of membership. She could buy the electronic calculator but I don't know about the slide. I think you have to get those from the leader. She could do it with the formula and then she wouldn't need the slide:

Calories x 2 / 100 + .1 x grams of fat - .2 x grams of fiber (up to 4 grams) = Points

Example: 125 calories, 5 grams of fat, 6 grams of fiber
125 x 2 / 100 = 2.5
.1 x 5 = .5
.2 x 4 = -.8
TOTAL POINTS = 3.2 which I would round to 3

You can also find things on ebay all the time.

I will let my friend know. I am sure she will be thrilled to at least be able to do WW at home.