How to download music directly to iPhones library without a computer?

Alright, so I just switched from a galaxy to an iphone, and one of the bad things is that I can't directly download music to my iphone like I could with my galaxy.

I had more than 500 songs and I don't wanna pay.99 or 1.29 for each song. Some of my songs are not even on iTunes.

I don't really want to use the computer just because I don't use mines that often.plus I'm always using my phone and it's just a lot easier

is there a way I can directly download music to my iPhones ORIGINAL music library without a computer, not with one of the apps from the AppStore that only allows you to download music to their app…

The only way is with a computer if you want to here are the steps
1.Open Itunes
2.click top left corner "Add File To Library"
3.Choose each song you want to add
Hint: Use CTRL and left click to choose multiple songs at once
4.Sync Music