Android - In App Purchase to remove admob ad bar

I am developing an app for Google Play that will integrate an admob ad bar. I see many apps on the appstore offer in app purchases to remove ads and would like to do the same with my app.

Are there any tutorials or ways you can think of to achieve this by not using SavedPreferences or having to query with a database that I'd have to create.

I may sound lazy but I really want a solution that would query with a Google Play server rather than one I will have to create.

My reasoning is because a server I would create would take their device id and I want the in app purchase to carry across multiple devices under one Google Play account.