Great advice from these bros already. You didn't mention that you were planning AAS, didn't know since this is a steroid forum.....because sometimes there are specific supplements/vitamins/minerals that are good to supplement your diet with while on select gear.
That withstanding, I will add/reinforce:
Quality multivitamin and mineral supplement (liquid minerals are good)
GOOD flax seed oil (if inclined fish liver oil and/or evening primrose oil)
Glutamine
Zinc
Fast acting protein powder for immediately after workouts (such as whey isolate)
Don't listen to common folk or bros with little income that say all supplements are a rip-off, and a waste of your money, that's a farce. The recommendations you have heard in here should help you.
However, I will agree that you should never forget the word is SUPPLEMENT! Do your best to get your calories, protein, vitamins/minerals from whole foods first, and a quality diet. Sounds like motherly advice that anyone can give, but many seem to forget sometimes. Supplement what you have difficulty fulfilling in your diet based on your lifestyle.
I will add one more personal favorite, some bros may chastise because of fear, but I love it and it has helped me and CHEAP........I like to buy a container of beef and chicken liver at the grocery store (usually costs about $1.00). I squeeze and drain the liver blood, and add the blood this to some juice, milk, egg whites, or protein powder for a great source of protein. Very easily assimilated, and great for you if you can get over the taste. You can Usually lasts for about 4 or 5 days.
Good luck, stick around, you will get good advice from this forum.