Guess who still reads newspapers? Yep, it's people over the age of 40, the same demographic who are likely to have a garden and excess produce.
One year as an experiment I placed a wanted ad in my local newspaper that went something like this: Wanted: free/cheap excess garden fruit, lettuce, cucumbers, tomatoes, spinach. Call Andrew: (xxx) xxx-xxx.
I got about a dozen responses and ended up turning down most of them because it was more than I could eat. Newspaper ads will cost you some money, but they're effective in reaching your key old-person demographic.
I once placed an ad on Craigslist and got no responses, although it's free and it might be worth a shot for you. Also scan for other people's free fruit offers on the site.
A website which acts as a digital repository for harvest info on backyard and public property fruit trees all over the country is Neighborhood Fruit. Although their list is currently small, I'm hoping in time it will grow significantly.
At least in Connecticut, where I live, it's surprising how many orchards and farms have been bought by towns or open space foundations as a way of slowing over development.
Many of these properties sport still-productive-but-overgrown orchards. You just need to know where to look.
For instance, in this video I take you to overgrown apple orchard purchased by a nearbye town about a decade ago. I pillage is every fall, but can't eat even a fraction of the fruit there. I know of several more properties like this, and I'd be willing to bet the situation is similar in other parts of the the country.
If your town has an open space trust, start by perusing their property list online or by talking to an active member to see if they have any farms or orchards that might still be productive. Although towns might not advertise their open space, they probably have an open space committee. Find a member and ask them.
Although this sort of thing is rare on the east coast, on the west coast I've been to several city parks that sport fruit and nut trees. All you have to do is show up around harvest time and take whatever you like.
In addition to wild food foraging, learn how to buy food wholesale to save money.
Read how to store and ripen your fruit.
Learn about a healthy raw food diet.