omg it's so easy biggrin
If you have NX, get a shop and sell any items you have that you dont need, whether it be old armor or weapons from a previous level, scrolls/potions from a pq, etc. drops from monsters (some sell for a lot like charms of the undead), screws, magic rocks, etc. Get gachapon tickets because those will get you rich. Even if you can only afford 5. But if you can, get atleast 20. Then you'll be super mega rich >:] That's what i'm doing after Christmas ^^
If you don't have NX, don't bother selling things in FM entrance. Bad deals there. Just train on Sakura Cellions. After training on them for one hour, you'll have at least 150k :] So think, 5 hours of training = 750k. Not to mention their tails. ^^
It's better if you have an I/L wizard/mage for massive kills and KS'ing. If you don't have one, make one. It takes but a few hours to get to lvl 31 (hpq and kpq).