I have used KBB's website (Kelly Blue Book)

It gives you a reference point. But the best is doing research in the For Sale ad's in your area.

Same here, last one I traded in I looked up the Blue Book price.

I've stopped buying new over 10 years ago. And when I actually buy, the Model/Make is no where near where I started. One influence is reading owners responses on the make/model I'm looking for.

An example is the last time I've researched, I started out hell bent on a Lincoln. I ended up buying a Buick Lucerne (with little research on it but I know approx. what the value was), I then talked the salemans down to where I was comfortable and bought it.

After 4 years, no complaints

If you don't walk out on the salesman at least twice, you're not really trying.....haha

No, my time is valuable to me, just walking out once is fine, I can secure a deal before I get to the car I drove in with.

Formula for pricing used car:
((P1+P2)/2) * (A1/6) * (M1/5) = Asking Price

Where
P1 = What you think the car is worth ($$$)
P2 = Asking Price of similar car ($$$)
A1 = “I GOTTA get rid of this car!” = 4, 5, 6, 7 = "I don’t really care if the car ever sells."
M1 = “I could REALLY use the money!” = 4, 5, 6 = "I don’t really care if the car ever sells."

Some sort of sliding time scale is then applied to Asking Price. In short, The higher the values of M1 and A1, the more time it takes for the scale to have any effect on asking price.

Selling Price = First guy with cash in hand that offers Asking Price minus 5%.

I'm in the business and even I have trouble pricing used cars. Right now, the used car market is shifting. From 2008 'til earlier this year, there was a shortage of "good" used cars. Then the lease returns came flooding the market and now there's an abundance of "good" used cars. The truck and crossover market is still tight and prices are still way too high.

A couple weeks ago, I sold a 2010 Toyota Tacoma Regular Cab pick up truck "shortie". 113K miles, clean truck, 4 cyl, auto, manual windows and locks. Overall good cond with slight body damage at bottom of cab and bed. I sold it for $12,110, which was retail KBB (book). I now have another client that wants that truck and I can't find one for the price I sold it = I sold it for too low a price. I've been doing this since 2002 and I've delivered over 3,000 cars, so I typically don't make mistakes like this, but when the market is off, it happens.

Here's another example. I took an early lease return on a 2013 Honda Civic LX sedan, silver with 42K miles - very clean car. Lease payoff is a hair over $12K, so I figured I'm in good shape. I called my wholesaler to sell it and I got hit with $11,500. Luckily, I paid the last payment of $220ish and I'm driving the car for two months. If I sell it, that's good, but if not, at least I have a back door. About 3-4 months ago, I was looking for this same car for a client and I couldn't buy a clean one for less than $13,200 my cost. I wound up putting them in a new 2016 for $18,800 - zero miles and full warranty.

I'm not sold on buying used cars when the market is high. I just got our daughter a 2016 Camry SE with a sunroof for $181/mo (inc tax) and $0 drive off for a 24 month/12K mile a year lease. Comes with 2 years/25,000 mile free maintenance. To purchase a used car and get the same payment, you'd have to buy a $9,250 car with 60 month payments and 1.99% interest rate and you'll get stuck with the repair/maint costs.