Starting early is smart, I suggest using a tool such as fit day. I don't agree with super low carb, high protein diets, they are crash dieting and your body pays for it. Find what your daily caloric intake should be, this can be determined by a few different websites simply google it. Once you have a base caloric intake (the amount your body needs to function in a single day) figure out what you are burning roughly during your exercises. I've seen guys post what a moderate 30 min roll is but I forget it off the top of my head. Try to maintain as negative of a caloric intake as you can (below your determined daily requirement) and your weight will begin to shred off.
Cost conscious is simple, go to the local store and buy chicken breast (hears the vegans screaming) and baby greens, spinach, carrots, apples. Mix it up, but stay away from greasy shit food, have fun with it. Fry up some chicken with some bell peppers in some olive oil, no need to be a chef, experiment and find what you like. I personally will take a small amount of peanut butter, mix it with olive oil baste my chicken with it and bake it. The key is to simply track your calories, which is simple as long as you note portions use either the items nutritional facts or google it. Find yourself a good vinagrette or two, they are super low in calories, taste great and are good for you.
Keep snacks ready, find some healthy snacks. I always keep carrots and cold peas in the fridge. If i get supper hungry i resort to that. I also usually keep some muscle milk light around. If i get a craving for something sweet, the 100 calorie packs come in handy and are great for before or after a hard practice when you find yourself not wanting to eat something heavy.
Don't be afraid to have a cheat day once a month and go out to eat with your girlfriend/friends and have that big ass greasy what ever it is you want, its the only thing that usually keeps you on the diet is knowing you can cheat form time to time. Try and keep away from the booze as much as you can, that shit sets you back farther then you can ever imagine. Nothing I like more then to tie one on with my buds, but the effects it will have on you can slow your progression for days.
Most of this stuff is all crap my sister (A registered clinical dietitian) has taught me and its not nearly as technical as she would cover it. The basic idea is eat healthy, good carbs (whole grain pasta), good protients(Chicken, lean beef, quality pork cuts) , good veggies and fruits, but balance it never to much of any single item.