Steam Greenlight allows developers to submit their games in order to receive feedback from users. However, the initiative has seen a number of inappropriate submissions - including one titled 'Best WTC Plane Simulator' - which have been taken down by Valve.
The listing fee is an attempt to discourage joke or fake submissions.
"There is unfortunately a significant amount of noise and clutter being submitted, either as a joke or by fans not fully understanding the purpose of Greenlight," explained a community post on Steam.
It continued by revealing that all proceeds received from submission fees will be donated to charity Child's Play.
Valve said: "We have no interest in making money from this, but we do need to cut down the noise in the system.
"Anyone who has already posted a submission to Greenlight will not have to retroactively pay for any existing submissions, but will need to do so for any future submissions."
Steam Greenlight has received more than 700 submissions since it was launched on August 30.