HOW TO MAKE YOUR OWN RINGTONES ON A LUMIA OR WINDOWS PHONE
To get start all you have to do is follow the steps below
1. Download the Ringtone Maker app from the Store, the Ringtone maker app can be found in Nokia Collections or by searching for it in the store. Alternately you can click on this LINK or here to get the Installation File (XAP)
2. Open the app and accept the terms by selecting Pick a Song
I kind of wished Nokia included apps like this on their phones out of the box.