Avril Lavigne's Here's To Never Growing Up is available to download for just $.69. I know it's a popular song right now.
There are actually a ton of mp3 downloads for $.69 right now at Amazon. I saw lots of current songs along with older songs from artists like P!nk, Journey, Radiohead, Miranda Lambert and tons of others.
Take a peek. I bet you'll find something you like. It's super easy to download them and you can save them on your Amazon cloud player or it will put them directly into your iTunes for you.