That depends on your strongest characters and/or level, AA's, gear etc.
From a recent post, you had said that your mage was 94 ish.
I am assuming that the 94 Mage is your highest character. If that is the case, then it would be hard to farm a lot of the higher demand items that could sell for the big coin in the bazaar. Such as some lvl 100-105 gear, a few 92-95 pieces that retained value such as Black Vertibrae or Chitin Stud (attunable/sell able earrings with EM focus), some Charms and also Dreadmotes (for 96-100 rk2 spells-turn in), especially the greater and glowing ones which sell in the bazaar above 30K each on my server ..sometimes as high as 50KPP for a glowing...
Then there are collections items, some of which sell for extremely high prices but I do not know much about that aspect of the game to give you further information on collection items.
On my server, a Krono now fetches an asking price of around 1 million Plat, sometimes more in the Bazaar.
So 12 million plat (to pay for a year of EQ via Krono) in a few weeks or a month is no easy task unless your at end game or at least max level..
Good luck.