app purchasing in same application

I have an application. I want to release this app in android market for free.

In my app there is purchase button.If user wants to purchase my app then click on purchase button then i want to show a billing page through android market.

I have done below example

http://developer.android.com/guide/market/billing/billing_integrate.html

I don't have any in app products just i want to purchase my app only.

In above example we got code like this

    new CatalogEntry("sword_001", R.string.two_handed_sword, Ma开发者_运维知识库naged.MANAGED),
    new CatalogEntry("potion_001", R.string.potions, Managed.UNMANAGED),

So where i need to keep my app id or package name in the code for identifying purchase my app.

And also i have another doubt

In paypal for every app there will be unique id. This unique id identifies the developer and transfers amount to the developer.

Then what is for in this integration(in app purchase).

For this i kept

String base64EncodedPublicKey ="my public key here"

is it correct or anything else.

Could please guide me to solve my problem.

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In this below link there is full information to implement In app billing.

http://developer.android.com/guide/market/billing/billing_integrate.html

I did small mistake i.e., i installed app in device with usb connection , not signed the apk with keystore file.

For this i faced the problem. After sign the application then i installed in phone.Now it is working well.