As others have already mentioned, there are round-about ways to still maintain your gil.

Personally, I would scout the market instead.
You can just create a new character on the server you wish to transfer to, then compare high value, high demand items to sell.
For starters you can look at materia, exclusive gardening seeds/mats, or exclusive myth tome crafting mats.

When I mean 'exclusive', I don't mean untradeable, but instead items that can only be obtained reliably by said means.
Such as Petrified Log is obtained by buying it with Myth tomes.
Glazenuts is obtained by gardening, and so on.