What are /r/Telecommunications' favorite Products & Services?

From 3.5 billion Reddit comments

We are glad that you like the top up experience with Kwikpay app. You can repeat your transactions for your favorite operator and amount from 'My Account' in your app. We will be thankful to you, if you can share your experience by rating our app at App Store https://itunes.apple.com/gb/app/kwikpay-mobile-top-up/id990590563?mt=8 & Google Play https://play.google.com/store/apps/details?id=com.uk.recharge.kwikpay&hl=en_GB