Can I play one song on my ipod and then have it turn off?

Yes. Create a playlist for the iPod with the one song you want to play.

On the iPod, go to the Settings screen and set Repeat to OFF.

Play the song from that playlist, where there is only that one song.

Now, if creating a playlist with only one song is inconvenient (because you want to use different songs), you can do it "on-the-fly" (on the iPod) by using the On-The-Go playlist feature. Find the song you want to use on the iPod. Select it and press/hold the Select button. You will get a menu, where you can select Add to On-The-Go. Then, go to your On-The-Go playlist, which only has that one song. Play it from there, as described above. It should play once and stop.