Currently, when you message a non-friend, there's a good chance it'll end up in a folder called "other." This folder is where the social networking site routes messages it deems less relevant - like messages from people you most likely don't know, based on Facebook's reading of your social connections.
But for $1, that message can instead pop up in the regular inbox, which means there's a better chance it'll actually get read.
Facebook is testing the feature on just a small percentage of users, not businesses.
"For example, if you want to send a message to someone you heard speak at an event but are not friends with, or if you want to message someone about a job opportunity, you can use this feature to reach their inbox," Facebook said in an online post. "For the receiver, this test allows them to hear from people who have an important message to send them."
The company said the $1 fee could help discourage spammers.
Earlier this year, Facebook unveiled another feature that lets users pay if they want more people to read their updates. For $7, users can promote a post to their friends, just as advertisers do.
The Associated Press contributed to this report.