Thank you for your message and i will be more than happy to guide you until you achieve your goal, your background seem enough to start the CEH training beside i will be available for your support whenever its needed, regarding the exam price is 1200USD however some times you will be able to get discounted voucher.
answering your questions about from where you can download Windows 8.1 , as i mentioned in my Video you can download the trial version from Microsoft website, this version will work for 180 days. kindly find below the download link and feel free to contact me if you face any problem or need any resources,
Before you begin. Make sure you have: An internet connection (internet service provider fees may apply). Sufficient data storage available on a computer, USB or external drive for the download.