After all the work you put into it, I feel not a little stupid, in need to ask you anything else. The truth is I am a slightly long in the tooth septuagenarian with about as much nous as someone dropping in on a day trip from the fourteenth century. I want to promote (tell as many people as possible) about my new book, and hopefully, sell one or two.
BigCommerce comes with a 15-day free trial for all plans. Their basic plans at $29.95 per month which comes with all the essential features that you will need. You can upgrade to the plus plan which costs $79.95 per month for additional conversion optimization features. Their pro plan costs $249.95 per month which has all the advanced features you may need.
Have just started to use their e-commerce features and agree they are awesome. By comparison I have just built an e-commerce site using BigCommerce and it has been a chore using their site builder. Also have a Shopify site on standby, but I think Weebly will end up being my site of choice, mainly because the guys listen and make every effort to accommodate the users.