Frugal dining for athletes
Oatmeal--the real kind that you cook on the stove, not the instant stuff. It will fuel you for just about anything.
Ditto Joebob's comment--chocolate milk is a classic and readily available recovery food. You perform on what you ate within the first hour after your last workout, not what you ate last night. Recovery is a huge part of getting in shape and yes, chocolate milk has a good ratio of both protein and carbs.
It's really hard to say without looking at your program. But, overall, I wouldn't worry about it. Most info about this and that when it comes to athletic performances are for elite level athletes. Unless you're spending double digit hours on high intensity exercises per week, I wouldn't worry about it.
For weight loss on the cheap, you just have to go with inexpensive ingredients like rice, pasta, beans and chicken. The big thing is that whenever you buy something, you should spend time looking for the servings per container and then dividing the portions up into separate containers. It's very easy to lose track of just how much you're consuming, so priority #1 is to get a handle on that.