There's no problem with gil. You could play only on the weekends and have more than enough gil. Lazy people complain against gil, go turn gear into materia instead of buying it. Take a half hour and farm up a few hundred thousand gil.... You've just got to be smart enough to look at the market and decide what is efficient to farm.

Or (god forbid) use your 99 leves and level a craft. Taking a craft to 50 might take you a while, but you can make money (maybe not tons) with any craft level 10+.

You only need to be level 35 miner/botanist to get any material from these jobs in the game. You can do botany to 35+ in a weekend.

If you don't like crafting/gathering classes then farm.