The distribution of ringtones for mobile phones is a very lucrative business if you consider that there are more than 3 billion mobile phones out there in the world. You can buy ringtones of every popular song in existence but it is rather hard to get those ringtones for free.
Toneshared is offering a large, free collection of electronic and alternative ringtones that can be downloaded right from their website. It is furthermore possible to listen to the ringtones before downloading them. Ringtones are sorted by artist, popularity and age. I don’t know any of the artists mentioned on Toneshared but if you like electronic music you might probably know some of them.