Should I buy a used Sigma 18-50mm lens for Sony APS-C?

Yes — the Sigma 18-50mm F2.8 DC DN for Sony E-mount APS-C is generally a strong used buy if you want a compact standard zoom with a constant f/2.8 aperture and good overall image quality.

The biggest reasons to consider it are its small size, relatively light weight, and fast aperture for a zoom in this class. Those traits make it a practical everyday lens for Sony APS-C bodies like the a6000 series.

One important tradeoff is that it does not have optical image stabilization, so you’ll rely on your camera’s stabilization, faster shutter speeds, or steady shooting technique.

If you buy used, check for clean glass, smooth autofocus, and any signs of fungus, haze, or heavy wear. If the price is fair and the lens is in good condition, it’s a solid option for Sony APS-C.