title: In app-billing implementation , buying paid app from free version
body: <p>I have paid and free version application in the single publisher account. now I have implemented the in-app billing implementation in free version I have added the in app product and done implementation in application code also. But what I want is user should able to buy the paid app from the free version app using the in app billing purchase. I am not getting how to add paid app as in app product and paid app get downloaded once user purchase the paid version.</p>