Reselling items on sites like eBay, Poshmark, and Mercari could earn you some extra pocket money. It could also evolve into a full-time, seven-figure business , like it has for Richard Senko, who started selling cellphones on eBay in 2008 after getting laid off from his job. Or, it could serve as a "double salary," as it does for Yinka Ogunsunlade, a full-time lawyer who earns six figures from his eBay side hustle, which he started in 2005. Whether you just want some extra cash to play with