How do i get free songs for my Ipod?

i have an Ipod Touch. I know about limewire. I've used it for months. But recently there was a virus in my computer, so i had to get it reprogrammed and lost everything. It might've been because of limewire, and i don't really trust it. So i don't want to download anything....but i'm not paying a dollar for one song everytime i want a new song. Thanks