Appcelerator Titanium: Yes

Appcelerator offers the Titanium+ program. There’s are three versions of this program and you need to chose either the small business or the enterprise versions. After reading complains from many users about high/excessive prices I tried to contact the publishers hoping I would be able to provide you with more detailed informations but Appcelerator never replied to my price request nor offers any infos on their site.

Read this for details.

rhomobile: No

There’s no support whatsoever for In-App payments in rhomobile. If you need to use the toolkit your only option is to extend rhomobile with native code.

PhoneGap: Yes (No official)

There’s no official support for In-App payments at the moment and there are no plans for it. But there’s an external plugin for PhoneGap available that acts as an wrapper for Apple StoreKit:

https://github.com/phonegap/phonegap-plugins/tree/master/iPhone/InAppPurchaseManager

MoSync: No (but annouced for future version)

Official support for StoreKit is announced and even if it wasn’t, it’s always possible to extend MoSync with native functions.

WidgetPad: No

There’s no StoreKit integration of any kind available. There are no plans to create support for it.

Adobe Flash/Flash Builder: No

There’s no StoreKit integration of any kind available. There are no plans to create support for it. It’s not possible to add this functionality since the runtime environment is under full control of Adobe and can’t be extended.