I can often be found selling and buying items on TradeMe. I love this independent auction and buying marketplace. Much better prices than in retail stores (typically) and huge variety. Listings change every week. Selling fees recently increased making the site a little less attractive for selling (now that Facebook gives local free selling options) - but it's still a great way to get reach and find buyers for your household goods etc.
Very unhappy with Trade Me. They recently shut my Trade Me account as they said it was part of my husbands account. It was not! When they did this they did not refund the money in my Trade Me account. When I emailed them about it (3 times) they did not reply. Not happy with Trade Me at all and will not open account again.