The Nokia 150 is equipped with a microSD memory card slot. If your laptop or personal computer is compatible with that kind of card (Most notebooks are so-equipped), you should be able to transfer music files
The Nokia 150 is equipped with Bluetooth version 3.0 (with SLAM), which lets you connect to your computer wirelessly. Just pair phone and computer together and drag and drop any music file from your computer to your Nokia 150.
If the above-mentioned methods fail or if you don't want to buy extra accessories, you can always use one of various free '3G Uploader' services available online. You should find plenty with a simple Katapulco.com search. 3G uploaders are easy to use: Transfer your own ringtones on their web site and they will return a URL. Pointing your Nokia 150's web browser to that address will download the free ringtone.
Learn more about making your own free ringtones
Here are links to some of the all free ringtones (compatible with your Nokia 150) we offer:
Free 'Unclassified' Ringtones Free Tropical Ringtones Free Ringtones-a-gogo Free Techno Ringtones Hear All Our Free Polyphonic Ringtones