Yes, you can access a practice exam in the NASM eLearning Center. Once logged in, select the NASM CPT 3 Online content and the practice exam will be at the bottom of the list.
Keep in mind that the practice exam is not to be used as a representation of the CPT examination. You should only be using it to quiz yourself of the various topics contained in the textbook. The practice exam is only one tool out of many to help you prepare for the examination. The actual CPT examination will be given through our third-party testing provider and it will not have the same visual look and feel. You have unlimited attempts on the practice exam.
You can also access valuable study tips through the NASM eLearning Center under the CPT 3 Online Resources tab.
Additional tools can also be found at: http://www.nasm.org/1/trainer_resources/Trainer_Resources_Overview/