My eBooks that I sell through this site are pdf files that are downloaded and can be printed. These are my own original techniques that I have invented myself, and they are not currently available from anywhere else with the exception of a lite version of the wood shells instructions which is available on Amazon Kindle. The information about making gears also includes a dimension calculator as a spreadsheet. This spreadsheet was made with Microsoft Excel, but can also be used with other spreadsheets that can open an xls file. Google documents can use this file and it is free. The Helix forms eBook includes a spreadsheet also, but it has graphics and macros that can only be used in Excel.
I do give a discount to subscribers as soon as they sign up - the discount code will be shown on the confirmation page. I prefer to use Paypal, and you can pay with Paypal even if you do not have an account with them. I also take U.S. money orders through regular mail and will send your files after it arrives. Send me an email to get mailing address. I also offer a multi-item discount which discounts $5 per additional eBook when you buy two or more at the same time.
If you have trouble understanding something in one of my eBooks then feel free to send an email and I will do the best I can to help.