Generally, it is around 15%, which depends on the specific situation, and there is no fixed proportion to calculate. Therefore, it is not only an extra delivery fee compared with the things in the physical store, but also a price difference, because the platform needs to make money from it, which is understandable.

And for fast food, of course, it's healthier to cook on the spot by ourselves. Therefore, we'd better not eat fast food often unless we have to. We can choose our favorite meals, and it's more reassuring and cheaper. Of course, we should judge by our free time. I hope my answer can give some help.