I want to transfer songs I've purchased from the "purchase" list to various playlists, but iTunes will not allow me to do this. This is incredibly frustrating, how can individual songs be transferred to a playlist?
You have to do right click on your iDevice in itunes and select tranfer purchased - this will copy your songs in the computer. After you do this you will be able to make playlist managing your song that you tranfered to your computer.
And don't forget first to authorize you computer with your apple id that you purchased the songs.