I picked up a 5 or 6 year old nutrition textbook from a used book store for less than 15$. It has pretty much all the nutritional information I'll ever need, not just how much of each nutrient you need, but what they all do, which foods have them, and so on.
Online, you could try the
NATS tool. It's not only a decent dietary analysis program, but you can find definitions and have it suggest foods for you.