I would not use a disposable container for my kid's lunch ever day -- seems very wasteful.
My kid uses a neoprene lunch bag (
http://www.amazon.com/BYO-Neoprene-Lunch-Monster-Mash-up/dp/B00F4AN9AO/ref=sr_1_2?ie=UTF8&qid=1421527335&sr=8-2&keywords=neoprene+lunch+sack).
Into the bag goes some combination of the following:
Rubbermaid LunchBlox sandwich kit -- it has a box that fits a sandwich, an icepack, and two smaller boxes. They all fit together.
or on cold days he sometimes gets a thermos with hot lunch.
Plus also kids' silverware. Which isn't entirely necessary, but the plastic-handled stuff is easy to write names on with sharpie.
Whatever you end up getting, I recommend getting at least two sets, so that set one goes in the dishwasher while set two is in use.