Valve, the video game publisher behind the hugely popular Steam platform, has introduced a process that lets players get paid for the game modifications they develop. Downloadable modifications, or mods, improve games by adding new features, and they’re almost always free. Until now.

“Elder Scrolls V: Skyrim” will be the first title to permit workshop creators to sell their mods, according to a blog post Valve published on Steam Thursday. This switch enables mod developers to create their own listings and charge whatever price they deem reasonable.

“With this update, community-made Workshop content such as mods, items or maps can now be made available for sale directly via the Steam workshop for titles that have enabled this feature,” the announcement said. “Workshop is now putting mod authors in business via a new streamlined process for listing, selling and managing their creations. Creators contributing to the Steam Workshop have the choice of listing their new creations for sale at a price of their choosing, or continue to make their work available to players for free. Mods purchased from the Steam Workshop are available immediately for play.”

Mod developers can still give something away for free. If their work sells, though, they take 25 percent of the profit and the rest of the money is split between Valve and “Skryim” developer Bethesda.

The reaction to the news has been mixed, with critics saying creativity doesn’t always mix with commercialism.

“To be quite honest, if I were a content creator I’d be pretty upset by this,” wrote Eric Kain, a Forbes magazine gaming contributor. “Sure, before they weren’t making anything. But a quarter of the proceeds strikes me as more insulting than modding for the love of it.”