Sinclair ZX Spectrum
Sinclair ZX SpectrumGetty Images

Technology is a fickle beast. New gadgets seem to arrive on the market and then fall out of fashion at an alarming rate, and it's always disheartening to sink hundreds of pounds on a new device only for it to be superseded months later by something better.

Whether it's fallen out of fashion or function, you can still make your old gadgets work for you by exchanging them for some cold hard cash. Popular devices from the 1980s and 1990s are still sought after today, and you'd be surprised at how much retro gadgets can sell for on places like eBay.

It's probably worth noting that amount you'll make depends on the condition of the item you're selling and factors such as whether it comes in its original box with manuals, accessories and the like. Also, trading on eBay ultimately comes down to pot luck, so while you might get less for your own items, there's every chance you could get more for them, too.

Sinclair ZX Spectrum

The legendary Sinclair ZX Spectrum (pictured above) is widely regarded as the grandfather of mainstream home computing. While its 8-bit architecture, 16KB RAM and 3.5MHz processor seem laughable by today's standards, when it was released in 1982 the ZX Spectrum was at the bleeding edge of home entertainment technology.

If you're willing to let go of a piece of gaming history, you could make anything up to £343 by flogging it online.

Sony casette Walkman
The original Sony Walkmansalenet/ eBay

Sony Walkman

Believe it or not, there was a time when Sony, not Apple, ruled the portable music player roost, famously kick-started by the Walkman. Sony lost the crown as the industry moved toward new music formats, yet its humble cassette player still retains its appeal. The TPS-L2 Walkman – the one that started it all – could fetch you nearly £350 on eBay.

Tamagotchi in 1997
TamagotchiReuters

Tamagotchi

Tamagotchis will be remembered fondly by those who grew up in the 1990s, when Bandai's pocket-sized digital pets were at the height of their popularity. They're still being churned out today, and although you can pick up a new model for £10 or so online, original Tamagotchis can sell for a staggering £255.

Apple Newton
The Apple Newtonhtomari/ Flickr

Apple Newton

Not all Apple products have been a runaway success like the iPod and iPhone, the Newton being one example. Released in 1993, Apple's PDA featured handwriting recognition that, despite being ahead of its time, fell short in practice. Combined with the device's high price, the Newton was consigned to an early grave.

If you happen to have one gathering dust in the attic, you could cash it in for up to £165.

Sony Hi-MD MZ-NH1
Sony's Hi-MD MZ-NH1 MiniDisc PlayerReuters

MiniDisc player

MiniDisc is widely seen as a failed format, although it did enjoy limited popularity during the interim between CD and MP3. One of the strongest players on the market was Sony's high-capacity MZ-RH1 player, which today sells on eBay for up to £300.

Sega Dreamcast
Sega DreamcastCourtesy

Sega Dreamcast

While being a competent machine with a decent gaming line-up, the 1998 Sega Dreamcast was quickly overshadowed by the launch of the PlayStation 2 in 2000. Sega stepped down from the console scene after that, yet love for its final outing remains, with Dreamcasts selling for nearly £200 on eBay.

iPhone First Generation
The original iPhoneDaniel Zanetti/ Wikimedia Commons

Original iPhone (first generation)

It was Apple's original iPhone than initiated the touchscreen revolution almost a decade ago, and it's done well to hold onto its value since then. A first-generation iPhone could bag you a tidy £171 on eBay, which rises to more than £300 if it's in mint condition.

Original Nintendo Game Boy
The original Nintendo Game BoyWilliam Warby/ Flickr

Nintendo Game Boy

The Nintendo Game Boy – surely the greatest handheld console of all time? It's definitely one of the best-selling, having shipped close to 120 million units and bested only by the Nintendo DS. It also boasted some of the best games of all time, including Pokémon Red and Blue which, by the way, will make you more than a pretty penny on eBay. As for the console itself, you're looking at upwards of £100.

How much have you made from your retro wares online? Let us know on Twitter @IBTimesUKTech