in-app-billing

I want to implement in-app billing for my application where users can purchase coins. However I want the users to get some free coins when they first try the game. How do I go about implementing this? If I just store it in the app settings, they can just keep re-installing the game and getting the free coins again. And the SD card is not secure enough, I don't want people tampering with it easily. I hope this isn't a duplicate but I looked around and couldn't find anything in the docs. Iv'e seen a few suggestions but they all include using your own server, which I do not want to do. App

I am building the "inapp" billing system in my application. After i execute skuDetails = mService.getSkuDetails(3, "my_app_package_name", "inapp", bundle); ArrayList<String> responseList = skuDetails.getStringArrayList("DETAILS_LIST"); I always get responseList.size() equal to 0, even if i have set 2 items in "in-app products" in the developer console, and i am passing them to: ArrayList<String> skuList = new ArrayList<String> (); skuList.add("first_id"); skuList.add("second_id"); Bundle bundle = new Bundle(); querySkus.putStringArrayList("ITEM_ID_LIST", bundle); The app is currently in Draft.

Currently I Am developing an magazine reader app. In my app I want to provide the Subscription facility where user can have monthly subscriptions. I am having a doubt that is there a subscription facility in android market. I went through the Google docs.I fond that now its not available. But still I am having a doubt and little bit confused. Can any one tell me about this. Any help will be appreciated.I really want to clarify this for the further movement. Yes, there is an API that facilitates subscription. It's called In-app Billing and it's one of the most difficult to use payment APIs I

since almost 2 months I'm searching for a solution for the following Problem. I implemented a library in my app which also includes the IInAppBillingService.aidl file and the other parts of the In App Billing Library from Google. When I'm trying to compile a release version of my app it just throws the following error: Error:Execution failed for task ':app:transformClassesWithJarMergingForRelease'. com.android.build.api.transform.TransformException: java.util.zip.ZipException: duplicate entry: com/android/vending/billing/IInAppBillingService$Stub$Proxy.class For the time being I was just using

I have an Android app with in-app subscriptions. While testing, I used a google account to "buy" a test subscription - the ones that last for 24 hours and don't incur in actual billing. It worked fine a few times, but my last "purchase" is stuck and I can't cancel it. When I try cancelling it via Google Play store, either the app or the website, I get these extremely unhelpful error messages: "An unexpected error occurred. Please try again later". When I try cancelling it via Google Play Developers API ( https://developers.google.com/android-publisher/api-ref/purchases/subscriptions/cancel )