Carousell

Carousell is a mobile-first marketplace where private individuals buy and sell directly: a photo and a price are almost all a listing needs. It was founded in 2012 by students from the National University of Singapore, and the city-state remains its core market. It also runs separate sites in Hong Kong, Malaysia, the Philippines and Taiwan, among others, and even in Australia and Canada. Second-hand goods from private sellers dominate, though small businesses sell there too, and terms are negotiated in the app's chat.

Collectors come for the personal collections that end up for sale: Gundam kits, Hot Toys figures, LEGO, trading cards, K-pop photocards, retro video games and vinyl, often priced by local rather than international standards. Each country's site has its own currency and listings in English, Chinese, Malay or Indonesian. Many sales end in a face-to-face handover, so it is worth checking first whether a seller ships abroad.