iTunes can take a lot of hard drive space, especially for a laptop with an SSD. But if you get an external drive, you can move your iTunes library to the external drive.
1. Copy the entire iTunes folder (~/Music/iTunes) (and all its subfolders and files) to the other drive.
2. Open iTunes while hold down the Option (alt) key (shift on Windows).
3. A dialog will show up, click "Choose Library..." and selected the iTunes folder you copied to the other drive.
