Coat Full of Contraband

A character is walking down a seedy alley, and is accosted by a man in a trenchcoat. He opens the coat to show a display of fake watches and asks the character, "You wanna buy a watch?"

This is a visual way of establishing a place or person as being shady. Often will be parodied by replacing the watches with whatever item likely to make the people around him go Squee and have a Nerdgasm. Another common variant is for the seller to be wearing numerous wristwatces on the same arm, pushing up his sleeve to display them.

The merchandise may have fallen off the back of a truck. The shady seller may be Honest John.

When adding examples, please remember that the trope is the visual of having the goods inside the coat or otherwise hidden from view.

Sister trope of Trench Coat Warfare where the coat is a coat of arms.

Examples of Coat Full of Contraband include:

Film

From Hercules: "Hey! Wanna buy a sundial?"
There's an illegal tomato dealer in Return of the Killer Tomatoes who pulls his wares out of the lining of his trenchcoat in this manner.
Happens in Jumper, somewhat ludicrously. The main character walks down a New York street particularly noted for these sort of dealers in search of a fake driver's license, and he's offered everything, from watches to children, but it turns out at least some or most are meant to ambush and rob the buyer.
In the film version of Ivan Vasilievich Changes Profession (a.k.a. Ivan Vasilievich: Back to the Future) there's a guy selling electronic parts that way, coat and all. Which is totally justified. In USSR, electronic parts were not outlawed, but private trade was.
Robots played with this, where a shady robot asks Rodney if he wants to buy a watch. The watches then say "don't buy us, we're fakes!"
Olive the Other Reindeer: the shady penguin Martini tries to sell Olive wristwatches from such an alley. He also has stationery and pens that he stole from the zoo when he escaped. More than one of these turns out to be a hilarious Chekhov's Gun.
Recess: School's Out had Hustler Kid ask Spinelli, "Wanna buy a Winger Dinger?" (Before you start giggling, a Winger Dinger is some sort of candy bar in the show)
Coming to America plays it fairly straight for a comedy when Hakeem and Semi are confronted with a man selling them some of the stuff stolen from them earlier in the film.

Literature

The Sleazy Guy in the Discworld video game sells hourglasses. When Rincewind asks where he got them from, he replies "fell off the back of a donkey cart".
- Cut-me-own-Throat Dibbler is most noted for selling nearly inedible food, but Guards! Guards! notes that he is also a "purveyor of absolutely anything that could be sold hurriedly from an open suitcase in a busy street and was guaranteed to have fallen off the back of an oxcart."
The S. Alan Fox short story "Technology Bites" has a "seedy-looking man" offering to sell the protagonist an awesome, next-generation computer (which fits neatly inside a raincoat). Unfortunately, it's just bait.
The cover of the December 1994 issue of Spy Magazine featured a Photoshopped image of then-President Bill Clinton selling a watch, Spam, a Cadillac hood ornament, a drink from Subway, and other items from inside his trench coat. Writers for the magazine pretended to represent Clinton, and called various companies stating that the President wanted to do product endorsements. They strung along the companies that said yes.

Live-Action TV

On Sesame Street, a green Anything Muppet guy keeps approaching Ernie with offers to sell him letters of the alphabet, among other things. The most famous short is called "Would You Like to Buy an 'O'?"
Lost has Sawyer doing stuff like this (with necklaces).
Parodied in the Goodies episode "Hype Pressure". Experiencing a 1950s revival, Tim turns into a quick-talking, quick-walking, shady spiv. "Wanna buy a nice pair of fluorescent socks?"
An episode of The Nanny played with the trope. Fran and Val are sitting on a park bench and a man with a long trenchcoat approaches them and holds it open. The audience only see him from the back, and the dialog at first implies he's flashing them, thanks to many innuendos until we finally see the watches. Later in the same episode, Fran sees the man and tries to summon him over to buy a watch, but he holds open his coat and flashes them instead.
In the Small Wonder episode "The Hustle", a street vendor calling himself Discount Eddie tricks Jamie into buying a portable TV set that doesn't work properly. Later, Ted confronts Eddie and is sold what appears to be a fur stole.
In an episode of Parker Lewis Can't Lose, a guy presents a selection of portable video games to Jerry Steiner.
In an episode of The Odd Couple, when Oscar is on a senior citizens' cruise for his ulcer, a guy has a trenchcoat full of junk food for sale.

Music

"Life Is a Carnival" by The Band. "Hey buddy, would you like to buy a watch real cheap?"
In one of Cheech and Chong's "Pedro & the Man" skits, the duo are approached in their stalled car by a Harlem youth offering them a watch, a transistor radio and a diamond ring.

Youth: Check it out, only real diamonds can cut glass!
Pedro: Hey, look what you did to my windshield, man!

Dan The Automator's mixtape Wanna Buy A Monkey? (named after the David Letterman line from Cabin Boy).
The video for Weird Al's White and Nerdy had him buying The Star Wars Holiday Special from such a vender.
Joe Jackson is depicted as wearing such a coat on the cover of his album I'm The Man.

Newspaper Comics

Clyde, the closest thing that Candorville has to a stereotypical black male, is often found selling these. On one occasion he used a similar approach to sell something highly secret—the main character thought it was drugs, but it turned out to be videos that were Guilty Pleasures.
The Far Side:
- "Hey, buddy.... You wanna buy a hoofed mammal?" Word of God says it was originally going to be "wanna buy an ungulate?" but he erred on the side of Viewers are Morons.
- Another one had a caveman in an overcoat, showing another caveman a campfire.
A Running Gag in The Wizard of Id's early days had one of these guys scamming Sir Rodney with items that were always exactly what he'd said they were, but naturally, never what he'd implied ("racy French postcards" that turned out to be of the Tour De France, for example).

Radio

A Running Gag on The Jack Benny Program was a shady-sounding man hissing to Jack, "Psst. Hey. Buddy. C'mere."

Theater

In Guys and Dolls, a shady watch seller distracts the Times Square crowd in the Opening Ballet. This also appears in the 1955 film adaptation.

Video Games

Ray in the Freddi Fish games, who's pretty much Honest John's Dealership without the dealership, sells these most of the time. Since this is a kids' series, it's never explained what's so dodgy about his merchandise.
Dragon Fable's weapon vendor.
The merchant from Resident Evil 4 very much gives off this vibe (and Talks Like A Pirate for some reason). He even peels back his trenchcoat in the standard manner when approached.

"Whad' a' ya' buyin'?"

Web Original

This Waverly Flams film. "Hey buddy! Wanna buy a ghost?"
The Strong Bad Email "licensed" has Strong Bad explaining how he and The Cheat have lent their likenesses to "officially licensed unlicensed merchandise" that is required to be sold this way. Bubs, an unlicensed unlicensed seller, is selling this way, but his goods are actually of a higher quality than what he sells at the concession stand.

Strong Bad: So wait a minute...your shady bootleg operation sells quality goods, while your legal storefront sells dangerous crap?!
Bubs: Exactly! I got a rep-uh-tation to uphold!

Western Animation

In Futurama, a shady salesman tries to sell Fry some 'bootlegged' alien organs. The salesman tries to sell him some gills, but says they won't come until next week. Meanwhile, he'll take the lungs, since Fry obviously won't need them, (and Fry agrees). Leela has to rescue him from the operating table.
A Cogsworth- lookalike seen in the House of Mouse short "Babysitters".
In the Ned's Newt episode "Newt York, Newt York", Newt turns into a shady watch dealer to try and "blend in with the locals" when visiting New York City. "Hey buddy, I've got a watch here that's you! Heck, I've even got one that was yours!"
One Where's Waldo illustration in a train station or airport shows (among many other things) a group of smugglers arrested, one carrying watches in his coat.

Truth in Television

There are lots of places to buy unlicensed knock offs and outright stolen merchandise in big cities, but the shadiest of shady vendors need to be able to deny what they're doing and walk off at at a moment's notice. Hence having lots of watches on your wrist, or in your pockets, or on the inside of your coat.