iPhone Storekit Helper Library

I have looked around for some resources relating to Apple's StoreKit framework on the iPhone and I really like the way Urban Airship's Store Front works. It is simple to use and the UI is already set up and everything. The problem is, they charge you $0.05 per download.

I have upgrades I would like to sell (basically it would download a small bit of data like an ID and "password" to access a certain feature, simply used to access content on my server), but 5 cents per download is quite a bit for what I have (I would definitely just use Store Front if I had a large file to download, but I don't).

My question is, is there something like Store Front i开发者_JS百科n the sense that it manages the purchases for you but is completely self managed? Any libraries with a prebuilt UI (or even just transaction management) would be really helpful...

Thanks!

Jiva Devoe's Cocoa Touch for iPhone OS 3 has a chapter on Store Kit that has a lot of what you're looking for. (At $40, it's roughly equivalent to 800 downloads from Urban Airship.)