Gil is no problem, even when you play casually.
Just loot your retainer, buy gear from your poetics and desync it, sell materia only on reset days, sell things you get in eureka/bozja and don't waste Gil for easy obtainable items.
You get a lot of gil and also don't really need any.
(Ohh, I've read the character name of the TE.
It is probably not worth to reply in a thread about Gil when the TE has the in-game name: Gil Seller)