Hello Thunderleg, Thank you for posting on the Final Fantasy XIV Technical Support Forums.

Yes that is true, a World Transfer from Congested to Preferred worlds are free. Although, the Statuses of Congested/Preferred Worlds change often. Currently Gilgamesh is not a Congested server. You can find most recent Statuses of Congested/Preferred Worlds on the Lodestone main page.

I hope I was of assistance.
Thank you for playing Final Fantasy XIV! Hope to see you online.