There are hundreds of "radio" apps, but only a tiny minority actually have a driver for your radio receiver. The rest are "internet radios" which pick an audio stream from one or a selection of streams from around the world. The internet radios need an internet connection, either wifi or through your cell provider, and you pay for that. The receiver apps need an earphone cord to use as an antenna, even if you use the speaker instead. You can then shut off your wifi and go to airplane mode and use much less power.
I use the non-descript "FM RADIO" app that has memory, recording, and puts out pretty good stereo sound. But I can't even find it again among the apps in the google store; might have come with my phone. I listen to our local classical music station on a cheap Blu Dash X when I'm out in the garden or woods.
You can find if your device is supported by nextradio (one of the tuner apps, but ad-supported) at http://nextradioapp.com/supported-device... .