Simple In App Purchase App Android
Does this library (AndroidBillingLibrary) solve your problem?
The current version of Android In App Purchase is V3
http://blog.blundellapps.com/simple-inapp-billing-payment-v3/
My blog post is titled Simple In App Purchase v2, so that might help:
http://blog.blundellapps.com/simple-inapp-billing-payment/
I've also recently written an overview with a flowchart to try and explain InApp Purchase (not so simple):
http://blog.blundellapps.com/overview-of-android-in-app-billing-flowchart/ (v2)