http://www.automotivetouchup.com/touch-up-paint/jeep/1998/cherokee/
I just bought all the stuff to do some work on my step dads Tundra from them. Test matched the color last weekend on the test trip that came with the supplies and they did a damn good job matching the color. I got all the supplies (prep, sanding, clearcoat...etc) and spent around $60. You could probably get away with just the the primer, paint & clear coat.
Problem with your Jeep though, no matter which company you use, it's most likely going to be darker than the rest of the Jeep. 17 years of the paint fading in the sun...
What I like about them is they have some very hard to find colors, especially for Toyota stuff. I was going to use Duplicolor but they had every other Toyota color except the one I needed. Maybe see if they have a listing on their site for the moss green?