Did you know that there are many ways to get free food. I want to give a HUGE SHOUT OUT to Ripe Near Me website. It is an amazing way for people to share their excess harvest from their Garden. I myself will use it once my bean's are done growing. If more people were aware of such a website then it would be over flowing with free food. I will use it to get my apples for my pies in October. There are other websites specific for certain regions, such as Share your yard Cultivate Toronto, and Ample Harvest.org I think that it is wonderful to see community come together to share in the passion they have in gardening. It would also be great for a seed swap as well. Folks check it out it may be valuable in a grid down SHTF situation when you are scavenging for scaps. Knowledge is POWER.
I didn't get the URL of the website...
http://ampleharvest.org/ and http://www.ripenear.me/
Here are some other useful websites for similar services based off a time honored tradition known as 'gleaning' which has been used since ancient times to feed those without the means to purchase food:
http://gleanings.org/
http://www.villageharvest.org/harvestingdirectory
Most are organizations based in California, but I'm sure if you contacted them they'd put you in direction for your local gleaning/volunteering organization.
A cool Ag-tech app is called crop-mobster which, while not always free, is still a cool service worth a mention (they sell excess produce to the public on the farm at a discount).
http://cropmobster.com/