I can't speak for Nutrisystem 100%, but I can tell you about Jenny Craig prices if you're interested.
I know someone on nutrisystem. I think for every day you need to add 2 servings of dairy, 2 fruit, and 2 veggie? I could be wrong. (Depends on the program you sign up for I think)
If that's the case, it depends on what you're buying. For my dairy, I tend to buy light soy milk (more expensive then skim milk), light string cheese, light yogurt. Veggies I tend to get celery, baby carrots, cucumber, salad, peas, broccoli...I get frozen and fresh. Assorted fruit depending on what looks good at the store and what's decently priced.