Another idea:
Why not use a webjukebox?
Free radiostations/websites will probably ask you to subscribe.
These kind of sites also have a tendency to generate banners, pop ups etc.
The alternative is to create a webjukebox on your website. This way you can control things by yourself: amount of mp3s, sequence, file format etc.
Recently we've created a jukebox on our website. We used the program Coffeecup Webjukebox. It's nothing fancy but it works rather well.
The interface is pretty straightforward and easy in use. You can choose from several skins.

The program and its visuals is probably way too simple for PGM grin , but it's just to give you an idea:

RnAM Jukebox

We're looking forward to the final concept!

Rob and Anne-Marie

We are Rob Meulman and Anne-Marie Bovenkamp from The Netherlands.

https://www.youtube.com/channel/UC1gsdNLE7_Gy8qavoOplQow/videos
http://rnam.net/