Online developers in the US have tapped into a long-standing Facebook retail trend by teaming up with PayPal.

The app, Soldsie, builds upon the trend of retailers – usually small-time operators – using the Facebook comment “sold” to sell individual items in photo galleries.

Merchants first install Soldsie on their Facebook account and get their fans to register with the startup, filling out payment and delivery info.

When posting images of items for sale on their page, those interested in buying simply leave a comment saying “SOLD”.

All comments containing the keyword are displayed on the seller’s Facebook dashboard, and from there they can send invoices and check on the status of orders and deliveries.

Payments are facilitated through PayPal, but sellers can use the Facebook dashboard to control and monitor their business activity.

Soldsie is currently offering a free 14-day trial that takes a three percent cut on sales if sellers make over USD 700 a month.

For more head to Springwise.