1) Crafting. If you get some of the not-cooking professions to at least 50, you can start making money with glamours, level 50 relic bases, glamour crystals, levequest and class quest items and housing items.
2) Weekly level 60 raid (24 man). The materia reward sells for 300k-500k for 30 minutes of effort.
3) Convert your Grand Company seals to the best selling items. Save all raid gear tokens (from the 8 mans) and blue quality gear so you can get seals with them in the next patch. Greed on all the green gear in dungeons to do the same with those.
4) If you have a fc room you can start basic gardening. Some plants go for twice as much as their seeds. I'm growing Thavnairian Onion at the moment, it's a plant that lets one raise their chocobo to rank 20. Always in demand.
5) Maps at level 60. There is no cooldown for this, just buy a map and get going with some friends who also bring maps. Walk away with more money than you spent.
6) Ventures. Free stuff is free money.
7) Level 44-48 beast tribe quests. After a certain rank you start to get materia with every quest.
8) Spiritbonding while leveling. A good way to make money back from any crafted items or vendor gear.
Also this. Don't powerlevel. Just use up your leve allowances and make all the items (that you can) yourself. This way it's almost free. With some foresight you can level gathering whilst simultaneously getting all the necessary materials for leves.
