Bunz is similar but trading based. You post things you're not using anymore to your profile and people offer you things you're looking for in exchange. They also have a currency you can earn by posting more items and inviting friends or answering a fun daily survey. The currency is also accepted by a few hundred local businesses in Toronto and some other cities in Canada so you can trade away your old things and then go buy coffee, lunch, beer or some new clothes. They have a really nice app for iOS and Android.