On topic, just doing dailies (EX Roulette, Ixal quests, hunts, occasionally levequests) literally every day, plus the weekly challenges that get completed from those, has made me a millionaire. I bought a small house for myself, which took me down to 30,000 gil, and now I'm back up over 3 million. If you can make even 10,000 gil a day doing dailies, you'll have a million gil every patch cycle (a little over 100 days).