When it comes to buying and selling things that you no longer want, Facebook trading sites have taken the place of consignment shops and garage sales.
But with thousands of people bartering and buying, there can be disputes and disagreements between buyers and sellers. There's an unwritten book of etiquette for these sites.
Consumer expert Amy Davis sat down with the administrators of some of the most popular trading sites in Houston to help you mind your Facebook manners.
Designer shoes, jewelry, baby gear, you name it, you can find a neighbor selling it on Facebook.
"I myself have bought a fabulous chair from this girl for $100, and I can't believe she sold it for $100," said Jackie Sharbrough, the administrator of West University Trading. "But I was so excited." Sharbrough started West University Trading so she could buy and sell items among her friends, but the group now has more than 6,500 members. That many people means many different personalities.
"Just be courteous," said Katie Bennett, who started the hugely popular Memorial Area Trading Facebook group.
Administrators of the sites often find themselves in the middle of disputes between buyers and sellers.
"In some extreme circumstances, we've had to remove a couple of people," said Laura Lam Ortiz, one of the administrators of Memorial Area Kids Trading.
While each group has its own rules, we asked Sharbrough, Bennett and Ortiz to share some etiquette guidelines. First, Sharbrough said bumping an item to the top of the feed too often by typing the word "bump" can be considered rude.
"It's like going to the grocery store and cutting in line," she said. "You're just cutting yourself back in line."
Sites like Memorial Area Trading can get dozens of posts a day, so if you're constantly pushing your sale post to the top, you're moving others down. The administrators say you shouldn't "bump" more often than every few days.
If you think a post is inappropriate or in violation of the rules, don't call someone out publicly or vent. There is a more discreet way to handle it.
"To the right of each post, there's a little arrow where you can click and get some more options," Bennett said. "You can report the post anonymously to the administrator."
When posting your own items for sale, be honest about the condition of the things you're selling.
"Show a picture of the flaw," said Ortiz. "Usually you just see a picture and it looks gorgeous."
And don't post and disappear.
"Once you post 'interested,' please make contact, communication right away," said Ortiz. You could send a private message to the seller."
"If you want to sell something, you want to go ahead and get rid of it, because you want your money or you want to get it out of your house," said Sharbrough, who said it's important to be quick about responding to sellers and buyers.
If you are not in a Facebook trading group and you would like to join one, search Facebook for the name of your area or neighborhood along with the word “trading.” Most groups are not public, so you might have to send a request to join.