Don't forget ventures. That's basically free money right there. The 18 hour Ventures you can send your retainer on always come back with the Allagan or whatever currency and can be worth a lot if you get your retainer up in levels and ilevel to where they can do the high ranked ones. Mine bring back $1k+ on each one, along with whatever items they brought back that can be sold.
I am not a crafter and rarely use the AH. From simply playing the game, leveling my characters, doing roulettes and beast tribe stuff, and retainers I hover at around 4 million all the time. I'll spend some every now and again to get a piece of gear for glamour, possibly some materia if I'm out of the one I want, but mostly, it's used to gear up that one job that needs an ilevel boost and I don't want to run roulettes or dungeons for hours and hours to get the tomes or possible item drops I would need to meet the ilevel jump from a new patch. My main job is never in this situation though.