really??? Onyx are much harder for me...
anyway... roaming arround in konquest is pretty good for Gold and Platinum koins..
Also.. play arcade in normal-hard difficulty... it pays well
OOOORRRR... u could get a list of the Krypt kontents and buy the koffins that give yyou gold koins... (That's good but kind of expensive)

i also find onyx to be the hardest to get....i need to get a bunch to unlock Noob/Smoke.....just started playing yesterday....all i have unlocked is Jade, a couple of puzzle fighters and cheesy artwork!.....how hard is it to find stuff in Konquest like keys and other goodies? Nearly impossible or super obvious/easy?

By far the easiest way to get gold and sometimes platinum is to win at chess. Also, you want to kill each and everyguy on the other team before you kill the leader so you can make the most Koinage.
I'm not sure if there's an easy way to get onyx coins. They were the hardest for me. I heard that if you keep beating the black dragon characters in chaosrealm (north eastern part maybe?), then you get tons of 'em. I never looked because by then I had everything. Another way to do it would be to start another Konquest file and the lose all those koins to your other file through VS. wagering, just a thought.

I already bought out all the koffins that give koins... I get Onyx and Platinum easily because I play puzzle kombat and thats all they give me!

ya puzzle gives onyx and plat
chess gives gold and some plat (i think lol)
arcade gives all the others
konquest is the master of koinage