I'm using the Custom Field Price from the marketplace and I'm wondering how I can get the price to update when the selection is made just like it does when I select a Characteristic of the same product. How can I get it to update the price on the product page instead of only being able to see the updated price in the cart?
There is no option for that.
That would require some javascript code to be added to the plugin to refresh the price area dynamically.
It's possible, but it requires a few hours of development.
