OK, all you computer people

Here's the deal - I'm looking for a cheap graphics program that I can use for a variety of uses. I don't need Photoshop, I won't be doing anything that fancy or high tech. But I am looking for a program that will allow me to do basic graphics without costing me an arm and a leg, since finances are rather tight. I had Microsoft Works from when I got a computer a decade ago, but it didn't run well on XP, and it ain't even gonna touch Vista. I did a few things for my unit and other organizations that needed simple graphics. Let me give you a few examples of the things I do.

The NCO Creed:


Here's a Certificate of Achievement I made for my Group Command Sergeant Major. He wanted something that could be used to recognize the Soldiers who did funeral details:




That's the sort of thing I need to be able to do. Any suggestions?