The 5 000 000 DP items are the Bandana (Infinite Ammo) and the Stealth Camo. (Completely Invisible). You don't need to buy them, if you complete the game on any difficulty without raising any alarms (cautions are ok) then you unlock the Stealth Camo. If you complete the game on any difficulty without killing anyone (tranq's and stuns are fine, so are unmanned enemies) you unlock the Bandana. If you play through and have no alerts or kills, you get a bonus of 40k. Also make sure your shopping on Wed. or Sat. as you get a 20% discount, and you get 50% all through act 5.