Whats a good site that lets you put free songs onto your cell phone?

I have Verizon, and I have the LG Cosmo. I know there are sites out there were you download free songs and then use the USB cable and put them on to your phone. But I would really like if you guys could please give me the ones that you guys like the best (the one that has the bigger selection of songs, etc...) So please only list the sites that have free songs and is legal. Thank You :)