S.T.A.L.K.E.R.: Clear Sky Cheats
You can do side missions for more money. They will be marked in yellow.
Bonus Vintar from Forester
When you complete the 'find the lost artifact' missions given to you by the Forester, he will give you a Vintar sniper. Watch for the sound and also the dialog text telling you that you received reward item Vintar. At this point if you get out of your conversation by pressing Escape of clicking on Exit, you will still have the Vintar but the...
Use it or Lose it
At some point in the game, you are asked to track Fang to the Flee Market in the Garbage. Before leaving the base, spend all your money on upgrades, weapons, etc. While tracking Fang, a couple of guys will rob you of your money and your stuff. You CANNOT recover your money, so use it all before this event occurs.