If I download songs to my IPhone and uninstall them, do I have to buy them again?

The problem is I bought some songs but now I want to delete them so I can put some fresh new songs but I still want the songs for my IPod. So if I delete them from my IPhone, will I have to buy them again? More information will be added if needed, thanks in advance, hope I explained it right.

No, you don't have to buy them again. You can find the purchased songs on your iTunes purchased history, so you can re-download it for free.

Can't uninstall a song, mostly cause there was nothing to install in the 1st place. Download & delete.

Assuming they were bought from the iTunes Store, then no. Once bought they are yours for life. Just get them again whenever via the Purchased section in iTunes.