I was wondering if there is a catalog script that I can get for free or pay for that would allow me to create an app in the apple store. It would only be a product gallery. There is no need for any functionality other than showing.
Ideally with folders.
We'd like to use it to show products to clients.
You seem to be VERY confused. Apps within the Apple app store are not some script which can simply be coded as you would for the web. Their proper executable applications which are written using the "Objective-C" programming language. If you want to produce an App that will work in the Apple App store you firstly have to own a Mac (because Apple won't let Windows users access their programming API) and secondly you need to learn that programming language and produce the app in a compiled format using their $99 system. Regarding what you're attempting... why not just make your website iDevice friendly?