Peerhub is a market place aimed at steemit users. Where users can buy or sell items for steem dollars. Paypal, cash and some other cryptocurrencies are also accepted.
"The Peerhub marketplace will now be focused around Steem dollars and the Steemit community. Just like Craigslist you can post listings for Goods, Services and Housing." quote taken from @steemrollin's peerhub introduction post on steemit.