I've recently become a bit obsessed with Poshmark. Poshmark is an app (also have web-based functionality) for buying & selling clothes, often secondhand but sometimes new too. I try to shop sustainably, which can be expensive, but secondhand clothing is a great way to keep things out of the landfill and save money. Plus, you're putting money into the hands of individuals rather than big corporations, which is a bonus. The app is easy to use, and I've had success with reselling some of my old clothes. I've gotten some really great deals too, which is slightly addictive.