Starting about this time of the year, if you live around farm country of any kind, you can sometimes gain a frugal coup by gleaning harvested fields.
We have gleaned potatoes, corn (which we fed to three huge turkeys - great Thanksgiving dinner that year!), onions, carrots and more. If you decide you want to glean, be sure and ask the farmer first. Some will let you, but some will not. Don't trespass without asking.
Also, if you live in farming country, keep your eyes open for produce spilled on the roads - especially side roads at corners where spills more frequently occur. I love to hop out and grab an onion or two when I see them, but it takes two people to do it right. The driver will pull up and stop, the passenger will jump out, grab the goodies and jump back in and the driver makes a getaway. Or something like that. :)
Spills will get you split or broken produce a lot of the time, but as long as it's fresh and you use it right away (dehydrate, can or freeze it), it's good food and it's free.
Is that extremely frugal, or just good sense?