You can now use your PayPal account to pay for purchases from Google’s Play Store. Canada is one of the 12 countries that can use their PayPal accounts to purchase apps, games, books, music, movies, and other in-app purchases. PayPal will be added as an option in Google Wallet. It will just require you to enter your PayPal login details. Google did not indicate if you will need to enter your login credentials every time though. Let us know when you try it out.
Source: Android Developers