You want SOLD LISTINGS. Not COMPLETED LISTINGS. completed listings include cars NOT sold. So you could have 300 model S listed at $200k that never sold but that doesn't represent their value whatsoever. That's like if you listing your house on the market for 3x it's market value. You can't appraise the value of your property by listing prices. You must look at the SOLD listings instead.
EBay's search tool is a little funky. Here are results for 2013 Tesla Model S, notice the results say 0 results found, however if you look at the listing they are marked sold. Could not get 2012 or 2014 results to come up.
http://www.ebay.com/sch/i.html?LH_I...efLoc=99&_dcat=180045&Model%20Year=2013&rt=nc