Real-time Notifications


I'm working on an SMS application whose primary feature will be sending real-time notifications. For the purpose of this question, I'll use the example of a cricket score update service. 

I would like to offer two account options, one free, basic, and supported via ads, one paid, customizable and free from ads.

The free service will send messages like "the score is now 180 runs, 40 overs" while the paid version will have options like sending a message saying "Yuvraj hit a six in Warne’s final over”.

I would like to know what monetization options are there for the free account?