Read the above post three times slowly. This is good advice.
Save as much money as you can while you're overseas, so its available to you when you return.
I go overseas frequently, and have some advice for you regarding what to take with you:
Take nothing with you that you wouldn't be okay leaving there. Between theft, misfortune, or accident, you may lose anything you take with you. Expensive jewelry comes to mind as a particularly poor choice. One gold coin, not so much of a problem, so long as you don't mind losing it. (How will you secure it when you shower? etc.) Whatever you take with you, plan on losing. That way when you lose it, it won't be a tremendous disappointment.
The very best thing you can take with you is a laptop, in a dust-proof pelican case. Read everything you can on your laptop, and write out a plan that you can work with when you return. Between saving every dollar you can and in-depth planning, that's likely the best use of your off-duty time while deployed. (You can watch movies and listen to music on a laptop, but you can't edit files, write a journal, and conduct in-depth planning on an iPod.) Take a camera with you, and have it on you at all times.
By the way, keep your head down and pay attention constantly to whats going on around you. Don't trust anyone over there, except your own guys.
Both my kids have been over there off and on for the past three years, and it takes a lot of self-discipline to avoid complacency.
Be safe, and thanks for serving.