Looking to upgrade from a D3300

Sigma 30mm f1.4 for $70, retail $500

Nikon Micro NIKKOR 105mm f/2.8G AF-S VR IF-ED Lens for $210, retail $800

How come these lenses are selling at a quarter or less of their original price? They seem fine. The retail price is incredibly high, yet the ebay price is so so low. These are both lenses I want, personally, at 1.4 and 2.8, they would be some of my best for my current interests.

/r/AskPhotography Thread Parent