How to add songs to my iPhone without iTunes on a mac?

Okay, this has been really frustrating me. I used to use CopyTransManager on my PC but I bought a Mac and figured, "How hard is it going to be to find an alternative?". Apparently very hard because I can't find a single piece of software, paid or free, that will take music from my computer and put them on my phone. I found plenty that say they will move the music into my iTunes library, but that is not what I want to do. I want to go the opposite way from my computer to my phone. Anyone know of software that will do this?

Added (1). That gave me nothing. Like at all.

No but search "mp3 music downloader free" on the App Store hoped I helped you