How do you buy music in animal crossing wild world

You don't buy the songs, K.K Slider gives them to you for free. To find him you have to go to the museum's coffee shop (The Roost) on Saturday when its past 8:00pm .
You'll see a white dog on the stage.You can't miss him. Talk to him and ask for a song. You can either request a song you know (you might hear one in your villagers house you like. You can see what its called if you press A at the radio.) or a random one willl be chosen. Sit down at the table and he will play you a song in Animalese (Their language, like, goo bat a pow a kon, o la de) When he finishes, he'll give you a CD that looks like a yellow music note in your pockets. (YOU CAN ONLY GEY ONE CD A NIGHT, UNLESS YOU HAVE MORE THAN ONE CHARACTER LIVING IN YOUR HOUSE) Go home and play it on your radio!