I’m super late posting this, as the news happened THREE YEARS AGO and the media didn’t spread the word. Anyway, as of 2017, the MP3 audio format is now patent-free. It doesn’t mean that you can now pirate all the commercial songs you want. What it actually means is now that the audio format is patent-free, you can implement an MP3 encoder/decoder into your game engine! That’s sweet!
It means if an operating system doesn’t natively support MP3 playback (ironically, as of 2020, most modern operating systems will natively support MP3 audio now), you can now provide code that will play MP3 audio. You can even distribute your own MP3 player or editor! But when it comes to your indie game, now you can distribute your original MP3 audio at a fraction of the source size, saving your end-user a lot of hard drive space!
However, do note, it is known that MP3 audio files might not be good for music looping. Apparently there is a fraction of a second reserved at the beginning of the format that might throw off the timing. So if you truly need precise audio looping, say for ambient background music in your game, then it’s probably best to stick with WAVE or OGG audio formats.
You can learn more about MP3 audio format at Wikipedia.