if you have AT&T or Sprint or Tmobile,
you can use Ventones to make and send free ringtones.

if you want full music, then you need to buy an SD card,. that will let you hold hundreds of songs depending on the size

Well, another victim of the perilously small memory card. What you can do about it: You can convert it into an m4a at a smaller bitrate. An m4a is a smaller, compressed-type file which is compatible with most phones. A smaller bitrate will also make the file smaller but it will not be as good quality. If you take a file from 192b to 128b, the difference is not noticeable, and unless you’re very picky it’s all good.
This is what I do in order to convert ringtones (Usually about 19-25 seconds long) into smaller files for my moto-slvr as I have no memory card at present.
If you’re converting whole songs and want more, you’ll need a bigger memory card. Most mp3 songs run at about 11megabytes; that’s about as small as some get.
My recommendation is that you get a larger memory card as well as converting songs to smaller file types. Hope this helps!