Peanut butter, bread +bread holders (I have enough to hold a whole loaf).
"Goobers" (peanut butter & jelly) and bagels. Plus, I hard boil eggs and take them with me.
I don't spend any money on trips except for van tips. That's it. I slam/click. I explain to the rest of the crew that I'm not being anti-social I'm just not spending any money.