digital media store shopping cart with admin panel(repost)

I am editing my project profile to be clear as I have gotten many responses for development of carts using 3rd party carts and admin panels. ? I am a new media company which deals with entertainment digital products. ? Most 3rd parties carts do not effectively deal with media downloadable products, and thus, their admin panels do not make this process user friendly. ? Also, most of the effective carts like mengento or other 3rd party carts charge money to use their service as a service provider. ? I am not interested in using 3rd party platforms to keep paying when I can easily use existing web stores like amazon or itunes and pay the same. See the rest of detailed explanation...