You need to be logged in to a verified account to purchase tracks.
Login by clicking "Login" at the top right on the Homepage. If your email is unverified, we will notify you and provide a button to send a verification email to your email. Login to your email and click the verification link to verify.
If you are already logged in to a verified account and still can’t purchase tracks, you have discovered a bug in our service. Contact us on firstname.lastname@example.org and we will get it fixed as soon as possible.