Kind of curious

I want to play music when I'm reading my bike. I could use my old mp3. But I have no way to download new music to it. So I may have to get a new mp3. Or if I could download music to my cellphone I would do it that way. But is there any sites I could download from for free. I notice like YouTube u need a membership. I'm not sure if that is to save on YouTube or download it to my cellphone