Buying and selling second-hand fashion items is now a very lucrative business

Online marketplaces like Depop has a wide customer base of younger users. Photo: Bloomberg

If finding new uses for old stuff is one of the core tenets of a sustainable business, some young influencers are taking that idea to the bank – by giving old fashions a new lease on life.

Millions of teens and twenty-somethings have embraced an app called Depop to buy and sell vintage shoes, accessories, or an old band T-shirt that's been gathering dust at the back of a closet.