I have an Apple ID and I have purchased some songs. My sister likes the same songs and wants them for her iPod Touch. I was wondering if I logged in with my Apple ID on her iPod and downloaded the same songs - would I have to pay again? I know Apple doesn't encourage ID sharing but my sister does't have a credit card or iTunes giftcard.
You won't be charged again. I have done this before in a similar situation, and it works fine. However, if the device gets restored or if the songs get deleted, you will have to sign in again to redownload them onto the device, which can be a pain.