More than 20 people appear on the name-and-shame list.
One contributor says: "It's extremely frustrating at the amount of people who dibs things and then fail to follow through. I don't know why? Do they go to the supermarket empty the trolley at checkout then change their mind?"
Another member complained when a sheep shearer asked for more time to pay because he had shouted his mates at the pub and spent the cash.
"Other shearers can pick up stuff they have agreed to, you can't go into a shop put a item on hold then say 'oh I sheared so many sheep today, I had to shout afterwards, can I pay later'," says the member.
Other complaints include selling items already sold for a higher price and general time wasters.
But these are the exceptions to the rule, according to the administrator Michelle Barre of Masterton.
"We don't have too many issues."
She said the overall success of the group reflects Wairarapa's community spirit.
"I think the Wairarapa as a community works really well together and the page shows that."
She started the group a few years ago to sell her son's clothes and toys and it was intended to be a small venture.
"I set it up originally because I had a lot of my son's clothes and toys to sell and it was free. It was just for family and friends and then people started asking me to join. It started to grow and grow," she said.
A second group administrator, Helen Lenton of Masterton, now shares the load.
Mrs Barre says there are a lot of reasons people like using the group.
"It's not having to pay a fee, the convenience of being able to pick up, and seeing the product first," she said.
