I traded in a 2004 package 0 (TRAC) w/ 13k miles, for a 2005 in 12/04. The dealer gave me exactly 20k for the trade, which is what the car cost new. I had no interest in selling it privately, because of the hassle and the fact that trading it in, in MN as in most states, saved me $1300 in sales tax on the new car. (So, I would have had to sell the car for $21,400 privately to cover the tax and advertising.) I think it makes sense to sell older, lower-priced cars privately (under $10k), but not late-model cars.
I paid MSRP minus $500 for the 2005, which was the deal that was agreed to from the start, so I know the trade-in value was not pumped up. (I was on a waitlist for 11 months.) In fact, I came up with the number I wanted myself, and they agreed to it pretty easily. The dealer then listed the car for $23k; don't know what they ended up selling it for.
I'll be trading in my 2005, which is a package 6, on a 2006 package 7 or 8 this winter. I'm paying MSRP -250 for the new one, and will expect the dealer to give me $25k for the trade, which will have 15-16k miles on it at the time. I'm also going to trade my wife's 2004 Accord in on a similar 2006 Prius for her, and will be lucky to get $20k for a car I spent over $25k to purchase new. It has 16k miles right now, NAV, leather, etc. Waitlists in MN were 4-6 months when I got back on them a few months back.
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