A) I need to provide my affiliates with the most basic shopping cart, that allows to sell products and offer discount coupons. Nothing more than that.

B) In addition to basic shopping cart functionalities, I also need to provide my affiliates with inventory control and order manager tools.

C) My affiliates need to ship their products. They will need to be able to automate USPS / UPS shipping cost calculations, or offer complex custom shipping rates. They might also need handing fee and sales tax calculation.

D) My affiliates will sell downloads, such as mp3 files, software ebooks etc. They will need tools that allow secure delivery of downloads and prevent illegal downloads from unauthorized users.

E) My affiliates will sell both tangible products and downloads. They will need all available shopping cart functionalities and tools.

F) My affiliates will host their websites on my server. I will need shopping cart set up for all their domain names.