Sayantani Mitra says she now scrolls through listings on Facebook Marketplace "for hours".
A 28-year-old from Oxford, prior to the pandemic she "would buy everything from charity shops, whether that's furniture, clothes, or bags and accessories".
But with lockdowns closing High Streets last year, her hunt for second-hand bargains switched to listings websites and apps.
Ms Mitra also now uses eBay and sites Vinted and Vestiaire, which both specialise in people selling pre-owned clothing. But she says that Facebook Marketplace is her "first place to go" because it focuses on sellers who live nearby.
"There's a thrill in finding something unique on there," says Ms Mitra, whose purchases over the past year have included a fridge freezer, plant stands, and a dining room table.
The boss of 香港集運淘寶 decoration brand Jurande, she adds: "It's convenient as I can collect from nearby. I have literally collected from around the corner."
Facebook does not release standalone financial details for Marketplace. It is in fact free for non-business users to put up a simple sales listing, as the firm makes it money from users simply being on its ecosystem and seeing all the advertisements on the site.
However, Marketplace's user numbers have soared during the pandemic. Facebook boss Mark Zuckerberg recently revealed that Marketplace now has more than one billion global users. This is up from a reported 800 million in 2018, for a service that was only launched in 2016.
At the same time, eBay says it saw a surge in the number of people in the UK selling second-hand items last year. It found that more than two-thirds of UK users said they had started selling pre-owned goods in 2020 to earn extra cash during the pandemic.
Ebay says that two second-hand fashion items were sold via its UK website and app every second in 2020.
"What we saw was a lot of people in their 香港集運淘寶s surrounded by their stuff, and looking at it every day and thinking 'what don't I need?', or realising they could make a bit of money out of it," says eBay's UK head of consumer selling, Emma Grant.
"Also, it was a time when people became money conscious. There's also been a surge in sustainable shopping, even beyond the people wanting to do the right thing, of finding joy in unique [second-hand] items."
For some people, such as 27-year-old Lapoze McTribouy, the pandemic has helped turn a hobby of selling second-hand clothing into a career.
She had been selling via pre-owned clothes website and app, Depop, on-and-off since 2013. But after being put on furlough last year, and then losing her job, she started to focus more on selling vintage clothing.
"I'd wanted to take it more seriously, and take it full time," says Ms McTribouy, who lives in London. "It was the right time."
She now sells about six items a week, many of which can fetch up to £150. "I live off this now," she says.
"It hasn't been an easy process though. People think you make money straight away, but I'd have months where I'd have to rely on my partner. But then others were, I'm like, 'we've got extra income'."
Ms McTribouy scouts charity shops, eBay and other vintage sellers for stock. "It's not just selling - you can put your creativity into whether that's the styling, or the background [you want an item of clothing to have]."
Depop reportedly now has more than 30 million global users, of which 90% are under 26. A UK business, it was bought last month by US ecommerce firm Etsy for $1.62bn (£1.2bn). Etsy's chief executive Josh Silverman called Depop "the resale 香港集運淘寶 for Gen-Z consumers".
While selling second-hand goods online has surged over the past year, there also appears to have been a big rise in people giving away things via websites and apps since the pandemic.
Olio is a UK app that allows people to give away surplus food and household items to people living near them. It reported a six-fold increase in the number of non-food items added to the app since March 2020.
Tiphaine Berger, a 38-year-old IT worker from York, says she has seen this boom first hand.
"Before the pandemic there was just one other person in the area on Olio," she says. "But it really boomed in the first lockdown because charity shops were closed. That was when people started donating, and getting rid of stuff.
"I use Olio because I hate waste. We de-cluttered and got rid of a lot of glasses and cups, then received plant pots, lamps, lights, picture frames, a new set of cushions."
But has all this online selling and donating had a negative impact on the UK's physical charity shops? Have they seen fewer donated items? Oxfam says that, thankfully, it has not, as many people still want to help good causes.
"All of our High Street shops were closed during lockdowns, and were not accepting donations," says Lorna Fallon, Oxfam's retail director. But the public has been really supportive and we have seen higher-than-average levels of donated goods since shops re-opened.
"We also launched a successful, free postal donation service in March that allows supporters to donate items without visiting a shop. Our supporters know that when they donate items to an Oxfam shop they are helping people to escape poverty and survive humanitarian disasters."
Mintel fashion analyst Tamara Sender says that the big increase in the buying and selling of second-hand clothing online has been led by young people who "in particular have suffered the financial consequences of the pandemic", and thus "they have become thriftier".
She adds that, pleasingly, charities are now increasingly being integrated into this new online world. "Depop has opened a British Heart Foundation online shop on its marketplace," she says. "And [another second-hand clothing seller] Asos Marketplace has also added products from numerous charities to its site.
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"As people increasingly buy second-hand fashion online, there is scope for more charity retailers to work with fashion brands to capitalise on the growing appetite for pre-loved fashion."
Cancer Research UK is one of the charities on Asos Marketplace. It also has collections on Depop, eBay, and Vestiare.
"Our online sales rose by 11% over the last year, and we're expecting to increase our online income by £1.5m in the next two years," says Josephine Mewett, head of retail operations at Cancer Research UK. "By donating pre-loved items and shopping with us, people are not only doing their bit for the environment, but also helping fund life-saving research to beat cancer."