100,000 different PDF files? Presuming you own the copyright to all of the content in those files (or have licenses from the copyright holders to resell their content), I'm not sure our service would even be practical for selling that many files. Our largest standard subscription level only allows for 7999 products, and each file needs to be a separate product; we may be able to devise a custom subscription plan for you, but it would still cost on the order of hundreds of dollars per month just for our service alone, not including Web hosting for your site and other expenses.
You would need to store all the actual files on your own server, and we may be able to import your products from a spreadsheet file (where you'd provide an Item Number, Item Name, Price and Remote File URL for each product). However, once the files have been imported, we have no way to edit product settings in bulk, so you could only make changes if needed to products by editing them one at a time.
You would also need a way to insert the purchase button codes for all of those products, since we are not a storefront-CMS that builds any sort of "online shop" site for you. The button code syntax is at least consistent, with only one variable that would need to be different for each product, so you could probably have a developer program some custom scripting that could populate your site with button codes based on the list of item numbers you provided in your import file.