Where to buy Fantasia?

[Pterodaryl]

What exactly does Fantasia do? Is it an aesthetic item?

Sorry for the noob question. At work so my internets are restricted, and only been playing for like 3 days.

[Niwashi]

What exactly does Fantasia do? Is it an aesthetic item?

It lets you change all appearance data on your character, even things like your race and gender. (It goes to a screen just like the original character creation screen with all the same character customization options). It does not, however, let you change your character's name (which some people find annoying if their name is race or gender specific and they end up playing a different race or gender which their name isn't appropriate to). You'll get one free Fantasia (per character) once you pay a month's subscription fee, and you can purchase additional ones for real money through the Mog Station.

There is also another feature in the game called the aeshetician which can let you change a lot of the more superficial appearance things (like hair style and color, etc). That one is unlocked by a quest (at level 17 IIRC) and can be done at any time for a payment in in-game gil.