At this week's Galaxy Unpacked event, Samsung opened the curtains on the Galaxy Z Fold 3 and Galaxy Z Flip 3. However, the Z Fold 3 is still pricey at $1,799, and while the Z Fold 3 is trying to reclaim its throne on our best foldable phones list (there is not much competition), this high price puts it out of reach for most consumers.

However, a quick glance at T-Mobile's Samsung Galaxy Z Fold 3 pre-order page reveals trade-in eligible devices: the iPhone 11 Pro, Samsung Galaxy S21, OnePlus 8 Pro, and other newer models. However, some of the devices eligible for trade-ins included older models that still offer ample returns.

In my case, it was a Samsung Galaxy S9 released over three years ago. The same trade-in deal also appears to be available on AT&T's Samsung Galaxy Z Fold 3 pre-order page, but only in Phantom Green and Phantom Silver colors. Verizon's Samsung Galaxy Z Fold 3 pre-order page also offers a trade-in of S9 is $1,000, but only for new lines.

This trade-in value seems crazy to me: a three-year-old phone for $1,000 on trade-in. For example, iPhones, which are known to hold their value, don't come close to that kind of retention. eBay listings show the 256GB iPhone XS Max selling in the $350 range.

I hopped over to Facebook Marketplace to see what I could pay for a used 64GB Galaxy S9. Most private sellers were offering around $200. However, I came across an S9 in good condition for $150. I sent a message.

Turns out, the seller was not an individual, but a local business in the Houston area. Houston is a large metropolitan area, so there is a fierce competition for phones and electronics. If you have ever been to an Asian city, you might notice that sellers in certain categories are clustered in one area. It's like that.

In Houston's case, this smartphone district is located on Harwin Drive, a street west of downtown and a little north of Houston's vibrant Chinatown. There I came across Wireless Liquidation, a small but modestly run store that supplies cell phones to presumably budget-minded buyers and small private sellers.

Upon entering the store, I found shelves lined with accessories and phone boxes. I started talking to one of the employees there and explained to him about T-Mobile's trade-in offers. He looked at me as if he were amused. But he was also curious. I bought a black Galaxy S9 for $150 (before tax) and he requested that I send him an update on Facebook after the trade-in.

At a nearby T-Mobile store, I was apparently the first person to walk in requesting a pre-order of the Galaxy Z Fold 3. While the foldable phone has generated a fair amount of publicity online, it has clearly not generated the wave of demand that the new iPhone has. (In fact, according to recent survey data, 44% of current iPhone owners in the U.S. plan to upgrade to an iPhone 13. By comparison, Galaxy S21 sales are said to be the worst in years, down 47% from the S10 series.)

The T-Mobile representative began the process of my trade-in request. She was also surprised at the $1,000 trade-in credit offered. She checked the system. If it weren't for the Z Fold 3 trade-in offer, a 64GB Galaxy S9 would normally only be a $45 credit.

After signing some paperwork, she was given a shipping label to send the Galaxy S9 and reserved a phantom green Samsung Galaxy Z Fold 3 for $950 (excluding tax).

There is a "desire to increase sales without resorting to obvious discounts that undermine perceived value," Avi Greengart, founder and principal analyst at Techsponential, said in an e-mail interview with Tom's guide. "And for carriers, these deals almost always include service level requirements, extended device payment terms, or both."

For example, Samsung took the bold step of trading in up to four devices (up to $800 total) for the Z Fold 3.

And let's not forget that you will be given a $1,000 billing credit, not a Visa gift card. Indeed, a personal $100 phone plan doesn't cost the carrier much.

When we spoke to our colleagues in tech journalism, our guess was that Samsung is doing whatever it can to bring new customers into the Galaxy ecosystem. The company's foldable handsets offer something consumers have never had before and could help the company form a new, loyal customer base, as it did with the Note series. Furthermore, with the closest competition being the Motorola Razr in 2019, there is not much else to switch to, at least until the rumored Google Pixel Fold and iPhone Flip hit the market.

In interviews I conducted with industry experts prior to the Z Fold 3 launch, I was told that large foldable phones would hit the $1,000 or less mark in the next three years. The Galaxy Z Flip 3 certainly hit that big mark with a price starting at $999. And thanks to a trade-in offer with the more feature-rich Galaxy Z Fold 3, I'll be able to join the foldable fun before 2025.