WhatsApp has decided to simply eliminate their $1 Yearly Fee and go completely free. Don't worry though, they claim they are not planning on adding ads to make up the lost revenue. According to WhatsApp themselves,
"Naturally, people might wonder how we plan to keep WhatsApp running without subscription fees and if today's announcement means we're introducing third-party ads. The answer is no. Starting this year, we will test tools that allow you to use WhatsApp to communicate with businesses and organizations that you want to hear from. That could mean communicating with your bank about whether a recent transaction was fraudulent, or with an airline about a delayed flight. We all get these messages elsewhere today – through text messages and phone calls – so we want to test new tools to make this easier to do on WhatsApp, while still giving you an experience without third-party ads and spam."
This pricing change is going into effect starting today.
Source: WhatsApp