game traders
Buy him from eBay
A company named "Lego" has a Master Chief Halo figure listed on Amazon at the moment (March 2011) http://www.amazon.com/HALO-Master-Chief-Navy-Blue/dp/B001L18CK2 This may not be an official Lego product. However, it will interchange with Lego pieces. It is a complete figure. If you wish to make your own, BrickForge makes custom armor, BrickArms the guns. This is most likely where the parts for the "Lego" product above come from. It would be cheaper to buy the pieces and make your own, especially if you want more than one. Kubricks also has parts that interchange with Lego, including a Master Chief from Halo figure.
play.com
you buy an action replay
amazon
you have to buy action replay at the store
you need action replay
eBay
Ebay
Not much. You will only hear it in Firefight.
300,000 credits
you dont buy them u use action replay code