In 1989, a man at a Pennsylvania flea market bought a painting—ugly art, pretty frame—for $4. Once home, he removed the picture...and discovered under it one of the 24 original copies of the Declaration of Independence.

It later sold at a Sotheby’s auction for $2.4 million—proving yet again that one man’s trash really is another’s treasure.

Happily, we now have myriad ways—both online and off—to sort through all the world’s best “junk” and find jewels. In short, there are plenty of smart, simple money moves that can score you major bucks. Determined to score goodies on the cheap, I went exploring the world of extreme bargain hunting.

This is my map to hidden treasure.

1. Score on one-cent auction sites

“I won a TV for $5!” the ads say. Must be a scam, right? Not so fast.

Here’s how it works: Each bid starts at a penny and bids go up only a cent at a time, so if that TV sells for $5 (it does happen), it means the bid has been raised 500 times. Win, and you pay the $5 plus the 500 bids, for a total of $10—still a hell of a deal. And the site gets all the pennies from the losing bidders.

It feels like gambling, and it’s fun—I know, because I tried it on the site dealdash.com, which has auctions happening 24/7 (heads up: It’s less competition very late and very early), and it gets addictive fast. I bid on an oil painting (retail: $2,645; I bid $1.50), a flashlight ($60; I bid 21 cents), and towels ($150, I bid 52 cents), as well as toolboxes, a watch—I even bid on king-size sheets despite the fact that I don’t own a king-size bed. For only $2.01, why the hell not?

Finally, I bid a penny on a Dunkin’ Donuts $10 gift card—and won! Next round of jelly doughnuts is on me.

2. Mine for gold at your local thrift

First move: Pick the right place.

The Salvation Army and Goodwill are best because the donations are mountainous, and often the workers sorting and pricing them have a not-so-great grasp of what they’re worth. At a fancier thrift or antique-type store, deals can be rare.

Next: Reconnaissance. Chat up a worker and ask when donations usually come in. At my local thrift, I was told most people donate on weekends, so by week’s end, inventory has dwindled. Find the sweet spot.

Have patience. “Many thrifts are disorganized, so it takes great care to find things,” says Justin Cupler of thepennyhoarder.com, which is chock-full of money-saving ideas. “Move items, look in corners, dig through boxes.”

One of our 'MF' editors, a Jedi dumpster diver, found a brass-and-iron bed she then sold on Craiglist for $1,000.

And watch for new merch. One Saturday, I hit a thrift and combed through menswear, finding only Cosby sweaters, ugly shorts, white jeans (I can’t pull off white jeans)—just a whole lot of nothing. Then I spotted them: employees stocking shelves out of bins—the unspoiled goodies! I nabbed a perfect-fitting J.Lindeberg windbreaker ($10), a new sports coat ($15), and a 7 for All Mankind sweater ($12) that sells for $150.

Two more tricks: See a shopper with an item you want? Play it cool. Just tag along behind as he shops, then if he puts the item down—grab it! And never set something down thinking you’ll “come back for it.” Trust us, it won’t be there.

3. Find gems at yard, garage, and estate sales

Eternal vigilance isn’t just the price of freedom. It’s also the key to successful garage-and yard-saling.

I began by looking on yardsales.net for not-too-far-away sales (the better the neighborhood, the better the stuff) and watched for signs for nearby yard sales—even tiny sidewalk sales—I’d normally overlook.

Saturday morning, I hit my first spot and began sifting through junk. I even rummaged through kiddie stuff—and, voilà, a Macbook external keyboard.

Once you score, don’t be afraid to negotiate: “Yard sales are all about making deals,” Cupler says. “Scoop up some items you want and ask for a package deal. Don’t offend the seller by shooting too low, but asking for 25-50% off isn’t crazy.” (The keyboard was only $10, so I didn’t have the heart to try.)

Like the buzz? Try an estate sale—a sort of “garage sale on steroids” (especially if Gramps just died and the family is clearing out the house), says Pam Carlson of Ready Set Sale!

Find one on estatesales.net, she says, then pick your strategy. “For the best loot, be there early the first day to see the full inventory.” Want the deepest discounts? “Go the last hour of the last day—sellers don’t want to be stuck with the stff, so prices drop drastically.”

4. Dumpster dive for prizes

You don’t need to actually pick through swill or wallow in a dumpster to win the garbage game. Instead, hunt on “bulk-trash days” (most cities have them), when people toss out big stuff—furniture, TVs—and roam with an open eye.

The Jedi master of bulk-trash day (OK, any trash day), Men Fitness’ own Nina Combs, has found the following loot: a new Keurig coffee maker still in the box, a wood coffee table whose top rises to turn it into a desk, two antique lamps with silk shades, and a brass-and-iron bed she then sold on Craigslist for $1,000.

More amazing, a guy she knows found on the curb a Regency table that, refinished, sold at Christie’s for $20,000. That really happened. With these images dancing in my head, I went looking myself—and within an hour had found a pristine black dresser that fits my bedroom perfectly. Cost: $0. I was hooked.

Final pro tips from Combs: Yes, you do need to be wary of bedbugs, so research online to become an expert at spotting them. (Wood furniture with no cloth is safest.) And never hunt in a pile with mattresses or furniture wrapped tightly in plastic—a dead bedbug giveaway.

But the bedbug plague has an upside, too: If you spot a find you can’t cart right home, take paper and write “BEDBUGS” on it in big letters, then stick it on. Unlike with that item you’ll “come back for” at the thrift store, no one will touch it.

5. Flip your stuff into cash

What about your own junk? I realized I had a whole collection gathering dust: DVDs and Blu-rays. I’m too lazy to sell piecemeal on eBay, so I found decluttr.com. You scan barcodes (DVDs, books, tablets, etc.) with your phone, then get an instant price quote. I shipped a box to them for free—and got a check for $117!

My final haul

A $10 gift card, windbreaker, sports coat, sweater, keyboard, dresser, $117—and zero copies of the Declaration of Independence. But don’t think I’ve given up on that...