Ideally the script or app would be set up once so I could then simply edit the HTML on any page where I wanted it to appear again... Thanks in advance to anyone who can advise me how to do it and/or anyone who I could pay to implement it for me if it's beyond my abilities...
This can be done a number of ways, depending on what you like and need, see the following:
You could implement the code in a way so that you include the product info inside of it.
I would be happy to speak with you about a new theme or code customization if you would like, here is the theme that we use: https://media-in-laws-theme-2.myshopify.com/