I don't know if it's global, butt there used to be a thing on google maps where fruit trees growing on the side of the road etc would be marked.

Also you could try foraging, there are SOOO many plants that are edible and tons on 'edible weeds' etc

Also heaps of trees here and there with edible fruits that often get wasted. Last year I went and knocked on the neighbors door to see if they would let me have some of the fruit from their tree and they said to 'take as much as I wanted!' and offered me some plastic bags to do so :)

All kinds of plants are availableif you learn what is edible and how to accurately identify the plants :)

Just make sure you 'get' / borrow from the library / obtain a good field guide; or you could have a look at photographs (OBTAIN photographs / RETAIN knowledge of how to identify some of the various edible plants..

There are different variants of berries that grow wild and edible mushrooms, obviously BE SAFE AND MAKE SURE YOU ARE POSITIVE you have the right plant.

But I'd consider learning foraging and plant identification a pretty good investment.

Lentils are also very cheap, filling and good for you (+ I think they're yum!)

Plus you could check out the Wiki page for dumpster diving, I've pulled all kinds of amazing stuff out of dumpsters.

Almost everything you could think of.

The 'charities' here get so much things given to them that they run out of room and just chuck a whole bunch of PERFECT stuff in the dumpster to go to the tip. It's insane. You wouldn't believe if you saw what they throw away.

Kind of the same with the supermarkets, me and my ex used to go a couple of times a week and pull all of our vegetables out of the bin. One time we got a huge box filled with Ferrroro Rochere's....

Other good places are the back of bakery's in a relatively busy town. Got a huge sack of chocolate croissants and fancy bread one time.

my mates pulled AMAZING stuff out of the bins too. Cakes, bread, cheese, hummus, yoghurt, fruit etc... etc...

There was even a guy met traveling who only dumpster dived organic goods! Looked like he'd spent heaps on his food.

IF you do choose to dumpster dive though, you should check out the Wiki page; it's pretty informative.

And I wouldn't recommend doing it in tiny towns unless you REALLY have to.

But yeah, good luck :)