want n00b huh?
try playing conquest till you have almost 2k onyx and alot of others....
then unlock these koffins:
jg
nh
rh
tf
all of those trade your koins for onyx ones...totaling around 1600 onyx

Personally my favorite strategy is piss around on the computer and tell your girlfriend to run around in Konquest mode.
Seriously, I can't believe it, I thought I looked everywhere but she's found well over 1500 Onyx coins. I think I'm in love.

Thats funny, I had no problems with onyx coins but I had trouble with gold, I was short 1200 gold and had to go into regular MK and get them.

Chess and puzzle kombat give you onyx and platinum coins.

Thanx

I posted this in the "how many characters have you unlocked" thread. The northeast part of Chaos realm G-4 cross the bridge and defeat the Black Dragon clan. Go through the portal. Muchos onyx coins.
I'm molsen81 and I approve this message.

rofl wow thanks i just got noob :D

also in the netherealm:
at the cave to the very right of the desert type area at 10PM meat is in the cave for a VERY short time he gives you 1,000 onyx coins.
As well defeat Kabal, Cobra, Kira go to the portal platform and get a chest with 1,000 onyx coins.