There are so many free sources of P.T.C.E. information and practice questions (for example: https://www.test-guide.com/free-ptcb-practice-tests.html)13 online.
My suggestion would be to focus on the broad understanding of the P.T.C.B. test guidelines as found here: https://www.ptcb.org/guidebook/ptce-content-outline8
Personally, I found the book Mosby's Review for the Pharmacy Technician Certification Examination was very helpful when I has preparing for the exam.