You asked
Is the 7artisans af 25mm f 1 8 worth buying used?
Here is what the site says about that.
From 7Artisans AF 25mm f/1.8: 7Artisans AF 25mm f/1.8: A prime lens by 7Artisans for APS-C cameras, 25mm f/1.8. Specs - Maker: 7Artisans - Focal length: 25mm (prime) - Maximum aperture: f/1.8 - Made for: APS-C sensors - Mounts: Sony E, Fujifilm X, Nikon Z - Stabilised: no - Autofocus: yes What it frames like - On APS-C (Sony E, Fujifilm X, Nikon Z): like 38mm on full frame; f/1.8 gives about the depth of field of f/2.7 there. ...
From Buying used: Buying used: Cameras and lenses are built to last, and many photographers upgrade often. That makes the used market one of the best ways to afford good gear. A body that's one or two generations old is often most of the camera for a fraction of the price.
Quoted from this site's pages.