I did a quick flyby of Google Drive. You get 15 gigs, but it also works off you email account. In other words if you have 5 GB of email you would only have 10 GB of drive space. But man that is a lot of room. Not many ads at all and I posted a MP3 file up there and it worked fine. Now the bad part, I do not think there is a way to share out to the public. It looks like you need to email everyone an invite. That will not work.
Another thought I had was that most ISP providers give you some space up on the web for free. One would have to check out what is there and if it works well for sound files. I think some give you a couple GB of space maybe. At least 200 MB I would hope. Maybe not though, but check it out as it might work well and be the solution.
LB