You would need to pay Muzak or SiriusXM or another vetted provider of public music. Businesses (bars, hair salons, gyms, etc) cannot simply play Spotify or Pandora in their business, unless they plan on getting sued by BMI and/or ASCAP.

Muzak and SiriusXM have ready-made solutions for exactly what these sorts of businesses are looking for.

AMI Music?

iTunes used to have this. You could vote from your phone for a song playing on a PC. It was pretty neat when DJing for kids parties.