Pandora users wishing to upgrade from a free to paid account via the Android app can now manage their subscription directly in Google Play. Following a link in the settings of the app now takes you to a Play Store in-app purchase page to start the subscription. A Pandora One account will still set you back the same $3.99 (plus tax, at least in my state,) but this way it will be tied to your Google account. The terms right on the Play Store payment page explain that the app will continue to charge you on a monthly basis via Google Wallet.
This is a really nice way to manage subscriptions for many people, as having things tied to your Google account is usually better than individual logins and payment processes for each service. The new functionality is included in the latest version of the Pandora app, available at the Play Store link above.