Have you heard of gleaning? Wikipedia defines this practice as "the act of collecting leftover crops from farmers' fields after they have been commercially harvested or on fields where it is not economically profitable to harvest."
Today, gleaning can mean many things. It can mean contacting a local farmer and asking if you can come pick what's leftover in the fields for a low price. A friend of mine gathered boxes of sweet corn with her kids for just a few dollars every summer this way. It can also mean asking a homeowner if you can gather the falling plums going to waste on a tree you pass. Larger cities in the U.S. offer workshops and even pass on locations of free excess produce in cities like San Francisco.
Organizations also help coordinate help for hungry families through gleaning principles. The Society for St. Andrew explains their work as: "Gleaning is the traditional biblical practice of gathering crops that would otherwise be left in the fields to rot, or be plowed under after harvest. The Gleaning Network coordinates volunteers, growers, and distribution agencies to salvage this food for the needy." Food for Free is another organization that gets food excesses to those who could use it.
This picture shows another type of gleaning, one that we use in our family. The produce is from a farm family we buy from all summer and fall. We purchased the melons and squash at the normal price. The tomatoes are "canning grade" we bought at a reduced rate and they threw in one of the flats because they were going to go bad soon. The box of peppers were also tossed in since they were all imperfect (misshapen and such) and they had more than they could sell. This same farm family also sells pumpkins for a dollar apiece after Halloween when all the ones that are left would otherwise go to waste.