Every so often my friend Amanda will send me a picture on Snapchat or put up an Instagram poll with the caption “Should I?” The item in question? Always a pair of off-white sneakers worth hundreds of dollars.

Amanda spends $200 to $250 a month on these shoes. “Expensive sneakers have been a hobby of mine for 15 years,” she says. “I got into it in the late ’90s when I saw my older cousins and uncles wearing the latest Nikes — now, it’s a creative outlet for me. It’s fun, and I love it.”

I say no to her polls every time. I’ve never been able to understand how people can spend so much money on one pair of shoes — and sneakers no less.

Turns out, I may be the only one. Sneaker fever has sprinted (sorry) across the nation, with millennials — that dreaded word for humans between the ages of 23 and 38 — reportedly spending around $20 billion a year on sports footwear, according to Nasdaq.

To boot (sorry again), sales for sports footwear went up by a whopping 50 percent in 2017, the same study reports. This includes secondhand sneakers, which, despite being previously owned, do not diminish in price all that much.

Why Sneaker Resellers Are Popular

So why is this happening? Why are people so happy to throw money at these shoes, even if they’ve already been worn by someone else?

“There are two human traits behind almost every social trend,” says Daniel Levine, trends expert and director of the Avant-Guide Institute, a global trends expert company. “It’s the way we perceive ourselves and the way we want to be perceived by others.” For Levine, it’s about social inclusion.

“The high-end sneaker trend speaks to both sensibilities of perception,” Levine adds. “People who collect rare sneakers usually live in a world where friends and colleagues are able to recognize these kicks as something special — they are social signifiers. People today earn ‘social credit’ for having the good taste, access, and money to acquire these status symbols.”

Nike and Adidas are, unsurprisingly, the most popular. Ironically, high-performance sports footwear has become more of a fashion statement than a sports-playing shoe.

Air Jordan, Yeezy, Converse, and Vans are set to take over the world at this rate, and it’s all about appearance.

“I think Yeezys, in particular, are very much run on hype,” says Alex Reichmann, CEO of iTest Cash, a retail security platform. “To start, Kanye West himself is highly popular, and he purposely makes all his shoes very limited edition.

“For almost all the Yeezy models, once they sell out, that’s it. They are then sold by people online at high prices. So ultimately, you combine a hip shoe with limited supply through a popular celebrity, and there seems to be a winning formula there. Supply and demand.

Sneaker Reselling Platforms

So it’s really no surprise that sales of secondhand or previously owned shoes from these companies are skyrocketing — it seems that many of us would do anything (or spend anything) to wear such a status symbol on our feet.

Add to that the nature of most of these brands being limited in number, and you’re on to a winner. Remember, supply and demand. The results of this are seen by the rise in online platforms that deal in the speedy (heh) reselling of high-class sneakers.

StockX

If you didn’t think that sneaker reselling was serious business before, you certainly will now. StockX goes one further than most other sites and, much like the Stock Exchange, from which it gets its name, it’s the world’s first stock market for retail with real ticker tape. The site acts as a live “bid/ask” marketplace — buyers place bids, sellers place asks, and when the bid and asks meet, the transaction happens automatically.

It gives a 100 percent authenticity guarantee on all its sneakers, so you know you’re not getting any duds, and also act as the middleman, eliminating the danger of getting scammed.

StockX incorporates real-time market data, making sure you’re getting the best price at that moment in time. It’s pretty cool — if I actually wanted a pair, I’d be swept off my feet. (Can’t stop, won’t stop. Puns will keep coming.)

The company seems to have what feels like every brand, make, and crossover of sports shoe known to humankind. At the bottom of the homepage, you can see the real-time tickers of each sneaker. I feel like I’m living in a utopian future where the world trades in shoes and not money. You never know. It could happen. Kanye’s gonna take over the world, anyway.

Bids range currently from $20 to an unbelievable $50,000 for a pair of Jordan 4 Retro Eminem Encore 2017 edition. My mind is blown. These are not just shoes — these are an investment. Suddenly, the stock market look makes sense.

StockX takes a fee of 9.5 percent from its sellers, with an additional 3 percent for payment processing. It also deals with handbags and watches. I’m almost afraid to look at the prices for those.

Goat.com

There’s nothing I enjoy more than a website name that has absolutely nothing to do with what it sells, and with Foot Locker having just invested $100 million into them, Goat is a serious competitor.

The company is similar to StockX in that it’s a prime reseller for sneakers, but in harsh contrast to StockX’s busy platform, Goat is completely minimalist. A largely white and black aesthetic, the only pop of color is the sneakers, meaning they’re the prime focus of your business on this site. It also doesn’t do bids.

Goat’s most expensive pair of sneakers is the simply named Adidas 3D Runner. That’s it. That’s the whole title. It’s a largely black shoe with a tiny sprinkling of orange and white along the side and will set you back another $50,000. Goat gives you the option of buying the shoe as new or used, but the prices honestly don’t differ all that much between the two.

In the used category, there is another option: Goat Clean. This category gives you the used shoe that has been professionally cleaned and authenticated by specialists. So you can either buy used from a randomer on the internet (an authenticated randomer, though) or get Goat Clean to take care of everything for you for an extra fee.

The shoe is then graded on a scale of “like new” to “good.” The world we live in, eh? First world problems . . .

The site is really straightforward and easy to use, and it provides endless categories to really narrow down your search. It offers an “Under Retail” section for those of you who are slightly more frugal about your sneakers but don’t like the idea of used shoes. Amazing.

It charges a pretty hefty fee of 9.5 to 20 percent, depending on your rating as a seller of shoes.

Stadium Goods

These guys are all about supporting sellers in their entrepreneurial endeavors. Stadium Goods wants to make your shoe-reselling business as easy and profitable as possible, but only if the shoes are not used. The sneakers can be pre-owned, but not pre-worn. That’s a serious selling point for them. And frankly, a lot more sanitary.

The site is the easiest to navigate of all these sellers, with each shoe type having its own section that can be immediately seen from the homepage. Its “Trophy Case” section separates all the rare or limited edition shoes from the others, and some of the most expensive ones run up to, you guessed it, $50,000 — this time for a pair of Air Jordan 11 Jeters. Sports stars have so much to answer for. I wonder whether some of them could easily afford the shoes named after them! Who am I kidding? Of course, they could.

Stadium Goods also has an awesome blog section that’s updated regularly with new shoes, trending shoes, and fun facts about sneakers. If you’re as obsessed as my friend Amanda, this will be your ultimate reading list for the week.

Something that didn’t occur to me until I saw this site is that most of these sneakers are for men. Stadium Goods has many sections for many types of shoes and then has one particular section dedicated to sneakers just for women.

While the other sites give you the option to choose women’s shoes from among the throng, the more expensive shoes are always for men.

Huh. I always knew it was a man’s world!

Stadium Goods takes 20 percent of the profits from a sold pair of sneakers.

ShoeKicker

This one is a little different from the rest. Rather than being a marketplace, ShoeKicker is a “shoe price search engine.” It researches dozens of stores to provide you with the best price for whatever particular pair of shoes you’re lusting after.

Unlike all the others who take fees for selling and handling, Shoekicker just sends you straight to the merchant to complete your order. This is ideal if you already know what type of sneaker you want, but you want to make sure you’re getting the best price.

It is less concerned with fashion statements than it is with shoes that are genuinely for running. So if you’re looking for collectibles or limited editions, this isn’t the one-stop shop for you. If you’re looking for something to run a marathon in, Shoekicker’s got you covered.

Final Thoughts

Buying secondhand or pre-owned sneakers makes sense when you sit and think about it. “It’s this eco-consciousness that drives the urge to buy secondhand,” says fashion psychologist Dawnn Karen. “You know where your product has come from. It stood the test of time. It’s durable. You can trust it, and you know that you’re reducing your footprint.” For Karen, secondhand clothes are assets and prized possessions in a way that newly manufactured clothes can’t be.

Sneaker buying and collecting is a hobby for so many people. It’s not necessarily about fitting in — like for Amanda, it’s about fun and creative expression. Doing research into the expensive sneakers you’re going to buy is paramount.

The fewer the shoes that are sold initially at full retail price, the heftier the resale value they’ll garner, because they’re rare.

So if a $50,000 pair of Jordans will bring you unlimited joy, and you have the money to spare, well, we’ve already seen they are an investment, so you could go for it. But be aware: At age 30, if you put that money away with a 6.6 percent compound interest rate of return, by the age of 60 you’d have $330,718.

But if you’re making yourself bankrupt for the sake of fitting in, that’s when you lose me. I still don’t know what I think about the whole market, but I understand it more now. And ain’t that a kick.