When Karen Green got a new job in 2007, some of her friends pitched in to buy her a brand-new iPhone.

And while hundreds of thousands of Americans clamored to get their hands on the first version of the revolutionary (as Apple correctly predicted) smartphone, Green wasn't one of them — in part because she had upgraded her new (non-smart) phone not long before and reportedly didn't want to switch from Verizon to AT&T.

"I didn't want to get rid of my new [not-smart] phone, and I figured it's an iPhone, so it'll never go out of date," Green told the daytime television program The Doctor & The Diva in 2019 (the same month that Apple unveiled the iPhone 11).

Green kept the first-generation, eight-gigabyte phone sealed in the box, realizing as the years went on that a collector might come to find it valuable. Her hunch was confirmed when appraisers on the show estimated it at $5,000.

But the results of an online auction shattered all expectations this weekend, when Green's iPhone sold for $63,356.40 — over 100 times more than its original cost, and more than any vintage iPhone before it.

Louisiana-based auction house LCG Auctions, which specializes in pop culture collectibles, described the phone as a hot-ticket item for collectors and investors alike. It "presents magnificently, showcasing sharp corners front and back, rich color, and 'case fresh' features," it said.

Some of those notable features include the phone's 2-megapixel camera and web browser, and the "iconic" box with a life-size image of an iPhone with 12 icons on its touchscreen.

LCG Auctions founder Mark Montero told NPR over email that because original iPhones were expensive ($599 for an 8 GB model) and their future impact not yet known, virtually all were opened and used as intended.

"To discover an original first release model from 2007 still brand new with its factory seal intact is truly remarkable," he wrote. "The great story behind it is just icing on the cake!"

Bidding started at $2,500 and ratcheted up quickly during 27 rounds. Montero told CNN that there were 10 bidders competing for the phone, which ultimately went to an unnamed individual from the U.S.

Other factory-sealed, first-edition iPhones have done well at recent auctions, selling for $35,414 last August and $39,339 in October.

But this particular phone is the first original model "in acceptable condition" to go up for auction since then, according to LCG. And it's expecting more record-breaking sales to come.

"High-end collectors operate by the 'Three R's' - relevance, rarity, and replaceability," Montero says. "A original factory sealed iPhone checks all the boxes and we believe it will only increase in value going forward."

How old iPhones became a hot new commodity

It's hard to overstate the historical significance of the original iPhone, which Apple CEO Steve Jobs introduced in January 2007.

"iPhone is a revolutionary and magical product that is literally five years ahead of any other mobile phone," Jobs said at the time. "We are all born with the ultimate pointing device — our fingers — and iPhone uses them to create the most revolutionary user interface since the mouse."

The iPhone became Apple's most successful product to date and earned the title of Time's invention of the year in 2007. Much has been said about how it has since changed the way humans communicate, work and live.

But why would someone shell out so much for one in 2023?

Some experts credit our collective cultural nostalgia (and the hype around Apple specifically) for fueling the vintage electronics market — even as the supply of unopened early iPhones remains extremely limited.

Bisrat Kinfemichael, a professor of accounting and finance at the New York Institute of Technology, told NPR over email that demand-side factors have made unopened first-generation iPhones into "extremely rare commodities, similar to precious metals."

People may place value on a product like an original iPhone for personal reasons in addition to its intrinsic value, he explains. That could be because of its nostalgic value, or because it "represents the beginning of a new era for advancements in smart devices."

Plus, Kinfemichael notes, the proliferation of online marketplaces (like eBay) has made it easier for buyers and sellers to find each other — and there may be more potential buyers now than ever.

"Substantial wealth has been created since the release of the original iPhone," he writes. "It is possible that some individuals who have benefited from the creation of wealth in the technology industry may highly value such devices and be willing to spend a lot of money on them."

Of course, not every old Apple gadget is fit for the auction block (in which case, consider recycling, selling or trading in your used iPhone).

Montero told Insider that LCG Auctions got lots of calls after its successful October sale, but "99% of them didn't have the same thing."

The notable exception is Green, who had decided to sell her phone to support her recently-opened cosmetic tattoo business. She told Insider that she otherwise wouldn't be in any rush to part with it.

As she put it, awestruck, on TV some four years ago: "What's it gonna be worth in 25 years?"