How do I get different gear/ masks in Halo 3?

I've tried the marketplace?


how do i get them? and how do I but stuff? give me your xbox live id to play me.How do I get different gear/ masks in Halo 3?
that other guy doesnt know that achievments arent what its all about. for example, the hayabusa armor is achieved when you get all the skulls, silver and gold. now, that doesnt mean that there arent some armors that are unlocked through achievements. See http://halo.wikia.com/wiki/Armor_Permuta鈥?/a> for more info.


PS the helmets, shoulders, and bodypieces for each set all have different requirements; except for the ones you start with, you will have do different things to get each part of the set (usually, the helmet is unlocked last and the task to unlock the set is related, though).How do I get different gear/ masks in Halo 3?
Unlocking achievements also unlock the armors.