So I have been searching around for a while now about how to add product options to my store pages where a customer will maybe click on an option from a dropdown box or a radio button and that then adds to the total price of the item they're trying to purchase.
I see where other people have asked this question and the answer seems to invariably be to use an app to do it.
Being an app developer this is complicated.
Apps may take time to load because it is waiting for other apps to load. If you add code in the theme.liquid and prioritize their app it should load in a fraction of a second.
Check out this example.
The app is only 35kb.
You could do all this yourself, but why create something that is already built and working.