You can make easy money after you have played the stage "Let Hecule Win!" playing with Android #18 in the Dragon Mission, simple purchase the Z difficulty and WE GOT THE POWER! and go to this Stage, go to a corner in the World Tournament Stage and let be hurled away from the arena and lose, if you are in the Z difficulty and got the WE GOT THE POWER! equipped in lvl. 5 you will win 120000 Zenny.
To take easy money you have to go to the saiyan saga and play the mini game of (CATCH BUBBLES!!!) with hard difficulty before you win the stage collect all the items of the planet. My best score is 25400 let's see what you are going to get!
To get the the characters you fought in dragon mission you have to go to warriors room, 1p, skill shop then go to the gray capsules and you will find there name and they cost either 2,000-5,000. Same with arena's but arena's cost 2,000-100,000.
Let the "Warrior" menu open on the bottom, then select Teen Gohan as your character. Equip Super Kamehameha, Kamehameha, Senzu Bean, WE GOTTA POWER, Transform and Warriors Body, then select any opponent, choose the Z difficulty level, when the battle begins move away from your opponent then charge your energy, make sure you have 5 bar or more, then transform into Super Saiyan 2 by pressing down+ki button, continue using Super Kamehameha by pressing up+ki button, your enemy can't evade this attack. Repeat this for easy win, you will get 230.000 zenie or more depend to your opponent.