Yes, most modern phones allow customization of ringtones for different contacts. Consult your phone's manual on how to do this.
Some sources, like audio editing apps, let you create your own ringtones from your favorite music.
Search ringtone download websites, ringtone apps, and even online discussion forums for recommendations from trusted sources.
Currently there are many websites to download free mp3 ringtones songs for you. I find it fast, convenient, and free.