How to resolve “The item you were attempting to purchase could not be found”

Question

I´m testing my in-app billing and followed the following steps:

Uploaded APK to the Market, created In-App items and published them (did not publish the app itself),

Answer 1

This error is telling you that you didn't add the item on Google play developer console under in-app product

Steps to add item

1. Login with Developer account in Google Play Developer Console.
2. Select the You App.
3. From left side Select In-app Products
4. Click on "+ Add new product" button
5. Add new Product window in open. Now enter product id and select Item Type
6. Click on "Continue"
7. Now new window is open. Now enter Title,Description,Price
8. Click on Save or Activate button

Note : If you click on Save button than the item in only save on your in-app products and it's still not active to use. you have to manually activate the item and wait for 2 or 3 hours to be active.

Most important : If you want to activate your item immediate than you have to click on Activate button at step 8. it will activate you item immediate and save it automatically.

Answer 2

Add your testers' accounts across all apps by following how to User-test a Google Play Billing app instructions.

Answer 3

If the app is not published, then the account you are using must be declared as a test account, check it here:

Setting Test accounts.