i have created a test application with in app product in google play. http://developer.android.com/guide/market/billing/billing_admin.html
i have added the billing part in my application. i have also added a product in google play. When i click the link from my application. Google play store is lunched with the correct name of my product. After 2seconds, i got this error:
Application error This version of the application is not configured bor billing through google play.check the help venter for more information
You need to sign your APK with your live certificate. Then install that onto your test device. You can then test InAppBilling.
If you are using the android.test.purchased it will work all the way, but you won't have the developerPayload in your final response.
If you are using your own draft in app item you can test all the way but you will be charged and so will have to refund it yourself afterwards.
You cannot buy items with the same gmail account that you use for the google play development console.
For more details see here: http://blog.blundell-apps.com/simple-inapp-billing-payment/
:D