OP have your daughter download all her CDs/friends' CDs to start...and if you search for download sites, there are many and some have very reasonable prices...just check and make sure it's a legit site..

There are also cheap download gift cards resold on ebay, I have seen $10-15 for 120 songs or something like that..I don't know which are the 'good' companies for downloads and itunes costs more than that, but there are lots of options good luck