I had to scour pinterest and landed on one of the first pins I ever pinned on my crafts board: This milk jug lunch box from lifehacker.com.
It's a very easy project and a good substitute for putting a sandwich in a plastic baggie every day (does using multiple baggies a day drive you crazy too? I feel like it's such a waste!!)
To make this, you just follow the guidelines on the website (very easy), cut along them, and fold. It says to use a button snap to hold it together (which had been keeping me from trying it before... I didn't know how to do this and was scared to try) but I just used a velcro dot instead with superglue.
On a related note... I made Logan and I egg salad sandwiches to take to work one day. I put mine in the pink re-usable sandwich container I had (store-bought, not this kind) and was nice enough to give Logan the blue and green one. I didn't think much of it, I thought I was being nice.
Apparently a 20-something should NOT be bringing a 'little boy' re-usable sandwich container into work and he was ridiculed endlessly all day.
I guess teachers can get away with these kinds of things.
After I made this and showed it to him, Logan actually said, 'Hey! Something they won't make fun of me for!!'
Yeah, we'll see.
Try this out if you bring a sandwich to work often!