Ask HN: Simplest way to sell and deliver a written research assessment?

I'm looking to:<p>- Allow a buyer to select the type of instrument and quantity (shopping cart) - Present a license agreement for them to agree to - Accept payment - Auto-ship the instrument by email or possibly let them download if that's better<p>I recognize that eCommerce is a thorny bush that can get very complicated and require a lot of work and some expertise to set up. I'm wondering if there's a relatively simple service provider or set of providers that makes this possible for someone with limited resources and limited technical ability.<p>Thanks!