Open the Steam Desktop App and hover over the tab. Select Market from the dropdown menu and filter by "Rust".
⚠️ : Skins rotate out every Thursday, and past items cannot be bought here. 🤝 Option 2: Steam Community Market buy rust skins
The only 100% official and guaranteed secure environment to buy skins that are no longer in the weekly store rotation. : Safety and massive variety. How to use : Open the Steam Desktop App and hover over the tab