Kung Fu Panda

Get to Level Zero (which is the level with all of the time trials)

Then when you are in the training room which explains how to juggle enemies (there is kind of a ten pin bowling formation of dummmies).. Do not kill them with a juggle, go into a panda roll/stumble and go back and forth. You get coins for hitting them. I notched up around 2000 coins in about 10-15 minutes.

You immediately get the coins aswell, you do not need to go and collect them as per the above solution where you can only get 8 at a time. Just keep rolling from door to door. You knock them all down in 2 goes.

EDIT - Looking back now I probably should add the most important part of the technique. You must roll into the wall/doors every time so you just keep on rolling as it turns you around 180 degrees.

This way you get roughly 40 every time you knock all of the 'pins' down.
Downright the easiest way to get this achievement.

(Upgrade your panda roll/stumble to 4 first, I never tried this on anything less....or input cheat 'Down- Right-Left-Up-Down' in the cheats menu for infinite chi)

EDIT -
Adding in what sadblossom mentioned. To attain this cheev you must also purchase the outfits. Thanks for the info.

"also please note that the upgrades are:basic stats, the panda moves, AND outfits. it wont pop until you get all in each! "

Just got this tonight, and I found that the best place to accumulate the rest of your coins needed after the two main playthroughs is on the Sand Level with the moonstones (level 10). After you fall down into the pit, you're going to want to "Panda Roll/Stumble" over and over and over again until you get the coins necessary to pay off what remains in the upgrade section. This took me little over 30 minutes to get the rest of my coins, and I had only beaten the game once on Dragon Warrior. Good luck!!

Also if you're up for putting in a cheat code to make this go faster, in the main menu, go under the "cheats" section and enter this: Down- Right-Left-Up-Down (this is for Infinite Chi so you can roll until you receive the necessary coin amount).

Peace.

When you are in the phase called Level Zero. Spend the first part there will begin the training time, in part they will teach you to lift the enemies he will be in training dummmies(bowling) WHAT you do not send them, but uses panda and the roll is beating them sothat they all be destroyed they will fall again each one you destroy them using the pandaroll you'll get 6 coins for each one you destroy.
(I was with the roller 4 Upgrade panda, do not know if it's to do without the upgrade)
I also put a video if anyone still has any doubts.

EASY MONEY Go to Level 3 training. When will teach you the shot A and B, do not do it and certainly not put you into a ball. You will then have a dozen dummy to destroy. Easy to make 5 a shot. Once you have a little money, buy immediately upgrade the CHI and CHARGE. It will make you more powerful and less consumer. Destroy models by putting you into a ball, because it relates parts, whereas striking models, it yields nothing. In 20 minutes, you can buy everything! What I did is that I put myself into a ball and then I went to bed my daughters. As reported destroyed models of CHI, the game plays itself. Returning, I had over 1000 credits. If you take the joystick to steer your panda is much faster.

So you pretty much want to beat the game. When that is said and done, go to load you're save file, load the one you beat but it will just bring you back to "the final fight" the boss fight. Just beat the level and you will get 300 coins, took me 5 min too beat the level on the dragon warrior setting.
Just remember that the panda stumble is you're best friend lol