[Jyaif]

Whether you like it or not, the fee is 0%.

Regarding the other costs:

> What about the overhead of hosting the site?

Hosting a static bag of bytes (e.g. a mobile app) costs nearly nothing. Just the cost of apple developer program (99$/year) would cover a huge amount of downloads.

> The cost to develop it?

Those are the same when developing an iOS app, except that with the web you would be able to target a much bigger market... if Safari was not actively slowing down the web.

> Drive traffic to it?

Breaking news, you also have to drive traffic to your app.

> Credit card processing fees? Managing fraud on payments?

Other people mentioned 2.9% on stripe. And if you are feeling adventurous, nothing spots you from creating your own payment system.