I would say one-half of the purchase price or less. Have seen this done before on higher-end, newer machines that have not gotten a lot of usage.
After I posted, I went to eBay and checked on "completed listings" for this model. The ones I saw that actually sold ranged in price from $2,000 to $2,600. (I did not go into individual listings to see how they would compare in detail to the machine you are looking at. You might want to do that. I think the higher end prices were the ones with the BSR and foot.)