Ideas for Brown Bagging?

Hello All! I'm six weeks postop, on full foods. I'm going to a Scrapbook Expo in a few weeks and already planning ahead on how to incorporate my new eating plan. We always brown-bag it because the food is so expensive. Any ideas on a high-protein lunch? I'll have my protein shake for breakfast on the road. I need something that doesn't need cooling, so I'm thinking maybe a small can of tuna. That's about as creative as I can get. Would love to hear your ideas!! Thanks so much! CathyB