You should NOT have to buy a Rule Book.
Your sponsor is REQUIRED as part of their accreditation to provide this free of charge, as well as amendments.
There is clearly something not right here. There are a whole series of questions that arise out of this. Are you sure your sponsor IS accreditied ?
Have you been asked to pay for a Rule Book ?
Have you been asked to pay for PPE ?
I would be very interested to learn the answers to these questions, as this sort of thing should not be happening these days. Please PM me if you wish, but I would strongly advise against buying a Rule Book as this will be money wasted.