I just went through this decision a month ago.
Here's what I went with:
Phone Plan: Tello Mobile $10 Pay-as-you-go credit
• Sprint service
• $10 activation fee including SIM card
• No annual fee. Use minutes/text/data until you run out of credit.
• You can enroll in an auto refill of credit too.
Phone: Kyocera Torque E6710 (Sprint)
• $24
• Pretty crappy specs in general but for calls/text/music it works well.
• Waterproof, military spec.
• It has an MicroSD slot to load tons of music.
• 4G LTE
This combo works really so far since I'm never so far from a major city or freeway that reception is an issue. You do have to be really cautious about data usage since it's prepaid. I use the ghostracer app and upload to strava over wifi when I'm home if I choose to track my runs with it. It has GPS + GLONASS too.