Please refer to these images to help guide you through your website details.
This is an example of the product page where the details are listed. (please see http://lexiartgallery.uk/product/pareidolia-limited-edition-print-by-david-munroe/ for full features and see how you can interact with the options here)
In this example, the product (which is a print) has multiple options (framed, canvas, size) which will vary the price accordingly. Please ensure you list all product variations (if applicable) in your details along with the price of each variation.
This is the most time consuming task of the website build where I enter all the details. Please ensure details are complete here.
You may need to do some shipping calculation research first in order to let me know what prices to enter.