When it comes to making money, I have made most of my money through the ways Tivia has nicely outlined. I make most of it (well made, not playing very much atm) through one of three ways; of which I'll share (even though we are now slightly off the topic of this tread

(1) Doing what Tivia does. The old buy low, sell high. Most of this comes stuff I've shopped around for, bought it, used it, and then sold it for a higher amount. (I bought a full set of Eisen gear for about 50k, used it, then sold it for about 120k) This is not a sure fire way to making gil. Sometimes this method will back fire on you or the expected profits will be just too low. Another thing is that other people may be onto the same “investing” that you are on and therefore you’ll have to keep your ideas fresh and keep your items varied.
(2) I use my craft; smithing. I do this by: (a) watching the market on smithing materials and products like a hawk and know what I can turn a profit on; and (b) making smithing consumables. The second way tends to be the more steady income way but the lower ROIC method. (If I mine my own ore I get an even higher ROIC at the cost of time.)
(3) Farming . . . bleh, not at my level. I don't do this as a major source income.
Okay back to the subject of this post -->
Now, even though many people have tricks and gimmicks to making gil the fact still stands that SE has a problem with outside businesses making money off of their product and abusing their game at the cost of the people who play this game legit (my opinion). As far as earning gil to buy the items I want to make myself a priceless Ninja, I'd rather not have to pay an overly-large sum of gil to a bunch pirates who will take the gil I spent so much time and effort on just to sell it for RL money and make a RL profit off of it. I believe this is wrong and needs to be stopped; if not at least addressed by SE.