Back in the old days before smartphones, the only way to get a custom ringtone without buying it from your servoce provider was to use an uploader. Like this one:
Phone Uploader
I use this website for my wife's LG Lotus Elite all the time. It puts the ringtone you want right into your ringtone folder. Works great, but there is a size limit. I'm not sure what it is but I tried uploading an entire 7MB song and it failed....said it was too big.