I was wondering, maybe now with the Script Editor App it is possible to edit the price on certain collection or tagged products? I was wondering if anyone has tried this out? Or if anyone has a code that I could look to adapt to our store? I want to add instead of decrease to set a shipping cost of specific products. Is this possible? Or maybe could I alter the shipping cost on an order before going to the checkout? Anyone know if anything of this is possible?
Shopify Scripts can only decrease the price on a line item - not add it.
I don't want to deviate the conversation to things other than Shopify Scripts here, but take a look at the CarrierService API. That will let you adjust the shipping price based on certain items in the cart.