We currently have a store in which every product has an additionnal fee in a metafield value. That fee needs to be applied to the product at checkout only for customers in a certain province. We haven’t found any app in the store that can do that and we also cannot find how we can do that using a private app.
The closest thing we found was the script editor, unfortunately the store doesn’t use Shopify Plus and it seems the scripts can’t access metafields.
Is it possible to have private apps or scripts in the theme modify prices at checkout?