If you're looking for an alternative to plastic containers and zip-top bags for food storage, consider LunchBots. The containers and their lids are available in four sizes and are made from 18/8 stainless steel that won't leach chemicals into food. Designed to fit in lunch boxes, backpacks, and even purses, LunchBots are dishwasher safe and are lab certified to be lead-free.
The Uno and Eco models each offer a single storage compartment: the Uno is sized for a burrito, sushi, or a sandwich, and the Eco is designed to hold larger portions. The Duo and Pico have two sections for separating foods. The Duo is the same size as the Uno but has a center divider. The Pico is a smaller version that's perfect for toddler snacks--or anyone looking to reduce portion sizes.
You can't put soup in these containers, as the lids are not watertight, but they are great for solid food. they cost about $13-$17 each. If you use a lot of bags, aluminum foil, or plastic wrap for your lunches, the containers will pay for themselves quickly.