This is not how i got rich in RO.
How i got rich in RO is alot lazier, and much more organic and long term.
But this isnt a topic about how i got rich, because i’ve found that nobody who i tell how i did it seems to be able to do the same, and the purpose of this topic is to be helpful.

You will need:
1. 1 merchant with atleast level 1 vend (job 10). This should take no more than a couple hours to get.
2. 1 Thief with atleast level 1 steal. Level 10 is preferable. A Job 10 thief should take no more than a couple hours to get.
3. Alot of patience.

If you already have a few million, and are wanting to kick that up to the next level, skip to phase 2.

Phase 1: Venture Capitol
Take your thief to one of the places where the “monster” Blue Plant spawns in a constant location. I’m working on a guide to where these farming spots are for blue (and other) plants.
Steal from the blue plants, and then kill them. Save the Blue Herbs, which are a 55% drop - with steal you should get almost 1 herb per plant.
Move the herbs to your merchant (using storage, obviously), and vend them overnight at the going rate on your server (propably 6-8k - check the recent prices on iro.snipah.com).
Do not spend zeny.
Continue this cycle until you have 4-5 million zeny.

Phase 2: Race in Hugel.
Move merchant with money to hugel (pront->geffen->alde->juno, then domestic airship from juno to hugel).
Save in hugel, then go the the lower left part of the map.
Go to the lower right corner of hugel - this is the monster racing area. You will likely see other players here.
At the hugel monster races, you bet on the outcome of monster races, and if you win, instead of winning more zeny, you get “prize medals”, which are non-transferable. You can trade 1000 of these for a slotted elemental armor worth ~200m (depending on the server you’re on).
You will note that there are announcements playing in hugel. When an announcement says that a monster race is open, talk to the appropriate npc (there is one for singles races, and one for doubles), and wager on the race.
He will move you to the racing arena. Go south, and talk to the npc behind the desk, and wager on the race. It doesnt matter what numbers you pick - the winners are random, and its just superstition what you bet on.
Sit back and wait until the race is over - you can watch the race if you want, but it gets boring mighty fast.
If you’ve won (note: in doubles, the order the monsters win in doesnt matter), walk north and a little west, and talk to the medal distributor (girl npc with an umbrella) to receive your medals.
Talk to the npc at the enterance of the arena to go back to hugel town. You’ll get automatically moved back if you wait more than 5 minutes (and if you let that happen, you dont get winnings if you havnt already claimed them).
Note: Sometimes you will get screwed out of your race money, if you enter the arena right before it closes, and cant talk to the npc in time. This sucks when it happens. Sometimes you will lose for hours or days straight. Do not lose patience.

You need 1000 medals to make a slotted elemental armor. You get 4 medals for winning the singles race, and 15 from winning a double race - with any given wager, the chance to win is 1/6 on singles, and 1/15 on doubles, so the doubles race is the one we should place a higher priority on, but a singles race is better than nothing. There is a 10 minute delay between races (A race is followed by 5 minutes for winners to claim thier prize, and 5 minutes of announcements about the next race), so you will spend most of your time waiting, doing homework, reading a book, posting on the iRO forums, or smoking pot. If we assume that you play in all 6 doubles races and 3 singles races per hour, you should make about 8 medals per hour, so it will take 125 hours on average, though it can vary very widely.

Continue doing this until you have 1000 medals.

Phase 3: Sell the elemental armor
You can take the 1000 medals to the factory in einbroch (ask a guide there), and “donate” them to an npc inside. Once you have donated 1000 medals, you get an option to receive your choice of slotted elemental armors.
With 500 medals, you can get a glittering jacket [1] - not a good deal
With 1500 medals, you can get your choice of a level 4 weapon. Most of these, however, are worth LESS than the slotted elemental armor which only costs 1000 medals to make.

Now, auction off your slotted elemental armor. Dont make the armor until you have a buyer, who can tell you what element of armor he wants - it’s better for both buyer and seller this way. Most players will want wind, but there are applications for water armor as well.

It isnt a fast process, but anyone can do it, and the payoff in the end is great - 200m is enough to equip several chars with good gear and have lots of money for leveing expenses as well.