You asked
Is the ttartisan 50mm f 1 2 worth buying used?
I don't list prices or used-market figures, so I can't tell you what this lens should cost secondhand. What I can tell you is what you'd be buying. It's a manual-focus 50mm f/1.2 made for APS-C cameras, and it frames like about 75mm on Sony E, Fujifilm X, Nikon Z and L-Mount bodies. It has no autofocus and no stabilisation, so it suits slow, deliberate shooting, especially portraits.
Used is a sensible way to buy gear like this, since good lenses last. See Buying used for how to approach it. Before you pay, check that the focus ring turns smoothly and that the glass is clean and free of haze or fungus. Then check the lens's camera list to confirm it fits the body you already own.
Written by Claude from this site's pages.