What inexpensive food should I take on a century?

I've been browsing some of the threads to answer this, but haven't come up with quite the right answer for me. I'm not going to buy Clif bars, speciality powders, or anything else I can't find in the grocery store.

I know from my 1st century that Gatorade is a good thing and I have plenty of that. Trail mix, not as great. Good for salt & sugar but too much protein.

I'm happy to make my own stuff if you have recipes. I have a couple weeks so I can squeeze some cooking time in.