For $1500 on eBay, you could pick up this custom Halo armor suit, complete with helmet and boots. One caveat: no weapons are included — plasma rifle would come in handy if you plan on wearing this in public. Auction page.
This is a custom-made actual wearable armor from Halo 3. It’s made for a 6ft+ person. Boot size is about 12, helmet size is medium to large. Padding and clips are included. Made of fiberglass, so it is very strong.