Personally I make most of my gil spiritbonding. A single hour of Urth's Gift returns a net profit of roughly 1.5 - 2 million gil. Do it for 5 hours during a weekend, and roughly another 7.5 - 10 million gil is gained.

I craft a little on the side, but as someone who doesn't have the endgame crafting gear, the sale of crafted items doesn't even come close to the income I generate through the sale of materia. So if it's just money you're looking for, I'd consider SB'ing instead.