I use royalty free musics and sound FXs in my game. Here are some royalty free music sites:
Actually most of my sound FXs and all the musics are purchased from this site. I also couldn't afford hundred of bucks per minute for musics but 10-20 bucks for one whole music is good for me. And they do have large number of musics which are costed between 10 - 30 dollars per one and royalty free and available for commercial use. So if you can spend some time and patiences search on the site, you may find something much better than you think.
This site do have many free music sources. But I think most of them are FXs, I haven't tried searching music on this site. And also you should pay attention to the licenses of the musics you searched on this site. Mostly if the license show 'Create Commons 0' (CC0), it means you can the music as free as you like.
Finally, you can check my game and see how royally free musics works:
There are totally 3 musics and 32 sound FXs in my game, and I totally spent about 150 dollars on all of them.