58250 checkout system & shoping cart

I am looking to purchase a script that I plan on reselling. I will ignore ALL bids over $80! I am looking for a checkout system and shopping cart that is very simple and it is for downloadable products only! I only request a few features. Features: -simple affiliate program can choose either percent of sale or set value -shopping cart -ability to add downloadable products. Customer downloads directly after payment is verified -payment with credit card and through paypal -should be able to add or subtract items to shopping cart -auto install feature for mysql table from install file. -download location should be secure, and not guessable Admin panel must include: -ability to add new products and upload there files -ability to change overall header and footer -can easily setup product pages Please leave your comments on the message board and let me know your ideas or questions!