American Girl
American Girl dolls get expensive in a hurry, even before you start buying yourself outfits that match your doll's. So it almost seems reasonable that the now-discontinued Kirsten goes for about $350 on eBay.
Of course, accessories help that price, and having a pre-Mattel, or even the original "white body" dolls made out of muslin will fetch a pretty penny more than that -- if you can find a buyer.
TMNT Channel 6 News Van
Even though this was basically the Ninja Turtles' Party Van with a fresh coat of paint, the Channel 6 news van is insanely sought-after today.
Depending on what all you have with it (bonus points for the green-suited April O'Neil that was included) you can fetch over $200 without the box. With the box? You could be looking at a whole lot more.
1959 Barbie
These days, there are so many Barbie iterations that we couldn't possibly keep up with them all. But in 1959, there was the one, the only original Barbie.
Assuming she's still in good condition, she could be worth up to $23,000.
Harry Potter and the Sorcerer's Stone First Edition
We all know and love the magical and astounding world of Harry Potter. The books swept the media into a storm. They threw you into a universe of unyielding magic, fantastical creatures and elements, and an ominous villain.
J.K. Rowling's Harry Potter series was and continues to be extremely popular today. And their value is just as relevant. The first edition of Harry Potter and the Sorcerer's Stone sold for $138, 600! That's crazy, right? And to further blow your mind, the First Edition novel is valued between $30,000 and $55,000.
Playmobil Victorian Dollhouse
We're not sure why 90s kids were fantasizing about old Victorian mansions, but in 1995, Playmobil released a dollhouse version that proved to be highly popular among collectors.
Today, it's appraised at about $1000.
Original Furby
Comics (the right ones)
There was a huge comics-industry crash in the '90s. Parents were snapping them up because they were collectible, and new publishers were springing up left and right, flooding the market with "Collectors' Editions" and new "Issue #1s" trying to get in on it.
As a result, most comics from the '80s and '90s aren't worth anything. But a few are. If you're one of the lucky people who has the Deadpool's first appearance in New Mutants #98, a graded copy in good condition went for $810 recently on eBay. However, grading can be a gamble, and you can still make plenty without -- consider this one that went for $226.
Hot Wheels
Not every Hot Wheels car you have lying around is going to make you rich, but if you've got the right one--specifically, the 1969 Volkswagen Beach Bomb--you're in luck.
It's been appraised by collectors as being worth as much as $125,000.
Old Video Games
Get the right old video game on your hands, and you could be in the money. Consider Earthbound, a quirky RPG for the Super Nintendo.
The "sold" listings on eBay seem to float around $170, but there's even one with the box included that went for $650.
Strawberry Shortcake Berry Happy Home Doll House
This is one where condition and accessories are huge. If you have a lot packaged with it, you can clear $250 pretty easily. Having the box never hurts, either.
There are a lot of these on eBay right now, and while some have gone for as little as $50, others have gone for $300 or more.
Tornado Rex
This board game was objectively awesome. The game pieces were these little plastic hikers trying to get up a mountain, and then Tornado Rex -- a Tasmanian Devil who was green for some reason -- would rip down the mountain in a spinning top, launched from the mountain summit, and if he knocked you off the board, you had to start over.
Honestly, you really just set the little dudes on the mountain and launched the top at them. The game goes (complete) for around $200, depending on condition.
Vlix
Did you know there were Star Wars cartoons before Clone Wars? They weren't very good, but they existed. One was about the Ewoks, and one told stories about what C-3PO and R2-D2 got up to in their spare time. One of the villains, the head of security for an interstellar gang, is a massively valuable action figure.
He only appeared in four episodes of a show nobody watched, but that's part of what makes him so valuable -- he was only ever made in Brazil, and he's super rare. Modern reproductions go for a hundred dollars or more, and vintage figures can set you back up to $4,000.
Black Lotus
Maybe it's because nerdy stuff wasn't as cool growing up as it is now, or maybe it's just because all those nerds grew up into computer science guys with huge paychecks, but nerd-hobbies are a great way to cash in.
The most ludicrous example of this is the Black Lotus, an incredibly rare, early card from the Magic: The Gathering card game. Here's one that went for over seven grand, but a signed, graded one can easily clear six figures.
The Empty Box the Old Video Game Came In
Sure, this isn't going to net as much money as the game itself, but did you know that the right cardboard box can net you $50?
That's how much the empty box for Super Metroid goes for on eBay, give or take a few bucks.
Garbage Pail Kids Cards
The Garbage Pail Kids were a hilarious and crass response to the more wholesome Cabbage Patch Kids of the 80s. At one point, trading cards were made for the franchise, and if you've still got them lying around, they could net you a hefty sum.
Specifically, the "Adam Bomb" card has been known to go for as much as $3000.
1978 Luke Skywalker Action Figure
Chances are, you probably don't have a 1978 Luke Skywalker action figure lying around--it's believed that there are only about 20 in existence.
But if you do, you might just be in luck. In 2015 a collector auctioned off his Star Wars collection, and Luke alone brought him in $25,000.
Classic PEZ Dispensers
PEZ was (and still is) a bizarre candy, made all the weirder by the dispensers that came with it. Who wouldn't want to eat chalky candy from the head of an iconic fictional character?
These days, certain dispensers can sell for thousands of dollars--including Mickey Mouse and Santa Claus.
Polly Pocket Sparkle Surprise
Polly Pocket was the tiny toy everyone loved. While there were lots of sets created for her, Sparkle Surprise is one of the best.
It recently sold for almost $500.
Original Monopoly
Monopoly is a board game all about making good investments, and if you happen to have an original edition from the 1930s lying around, you've made a good investment indeed.
These copies have been known to sell for as much as $3000 dollars.
Original Game Boy
For kids in the 90s, the original Game Boy was one hot-ticket item. Handheld video games were a game changer, and the Game Boy helped make that possible.
If you happen to have a mint condition one lying around, it could be worth over $500.
Mario Kart 64
Everyone's favorite plumber is also an accomplished racecar driver if the Mario Kart racing video games tell us anything.
If you happen to have a copy of Mario Kart 64 for the Nintendo 64, it might be time to cash in. Copies of the game have been known to sell for hundreds of dollars.
Bob Mackie Empress Bride Barbie
Out of the entire Barbie doll line, Bob Mackie Empress Bride Barbie is considered the ultimate bride doll.
These dolls are generally going for anywhere between $150-300.
Masters of the Universe Eternia Playset
Masters of the Universe was the hot superhero franchise of the 80s, and Mattel did their best to market the crap out of it to children with all sorts of toys and other tie-ins.
But it's the Eternia playset that collectors are after today. It can sell for up to $1600.
Teddy Ruxpin
Teddy Ruxpin was an animatronic bear from the 80s that could read stories to kids. But 80s kids probably know him better as a constant source of nightmare fuel.
If you happen to still have one of these creepy toys lying around, the terror might be worth it--they can sell for up to $500 today.
Original Lite Brite
Lite Brite had a simple premise but allowed for hours of creative fun.
Complete sets from the 70s can go for as much as $300 today.
G.I. Joe Missile Command Center
There are several G.I. Joe toys that sell for high dollar on the collector's market, but the Missile Command Center is probably one of the best.
It's been priced at $16,000.
Super Soaker
Of all the possible toys that could be worth good money today, the Super Soaker is probably the most puzzling.
But regardless, this plastic water gun has been known to sell for as much as $500.
Original Easy-Bake Oven
Only Easy-Bake Oven owners know the tedious thrill of cooking miniature baked goods in an oven powered by a light bulb.
For owners of the 1968 original edition, you'll be pleased to know that they sell for as much as $4000.
Wonder Bread He-Man
In one of the strangest cross-promotional gimmicks of all time, Wonder Bread partnered with Mattel to create a He-Man action figure in the 90s.
Weird as it might have been, these figures are now appraised at around $1000.