where is the best place to buy music for group fitness classes?

I also have bought from power music…. probably my favorite

and from muscle mixes:

https://www.musclemixes.com

and from dynamix:

https://www.dynamixmusic.com

It is so much easier now to do it all online. Most sites let you mix and match the songs you like, and sometimes change bpm.

On a related note, NPR did a really interesting series on workout mixes… not ones you would use as a professional, but a really interesting listen:

http://www.npr.org/series/123543591/sweatin-to-npr-workout-music