The cheapest way to get there that I know of (bar setting it to be your home Aetheryte) is to set Lima Lominsa to be a favourite Aetheryte destination, then teleport there from Western Thanalan (which is accessible via the Aethernet in Ul'dah). That's 170 gil, versus 200 taking the airship/boat. Since my home Aerthyte is Ul'dah, I use this method. Only saves 30 gil each time, but it's better than nothing.