Save by taking the time to bring your own food and beverages.
Storage: Glass containers are great for food that needs to be reheated in the microwave – it doesn't stain or warp as easily as plastic. If you don't need to heat things up, any ol' container will do.
Transport: Depending on the length of your commute, an insulated lunchbag can make sure your food doesn't get into the "danger zone." If your work doesn't have a communal refrigerator, this is even more imperative.
Liquids: Make sure you don't confuse thirst for hunger by staying hydrated during the day. Try screw-top water bottle for water, but if you prefer ice tea or sugary drinks, opt for a double-walled travel cup with straw (much easier to clean).