I just bought a 2006 F150 off Craiglist from a private seller. Much better price than the local dealers.
The low prices on newer models aren't ALL scams (although most of them are), some have rebuilt titles and some are high mileage.
Look at the photos of the vehicle background and see if the picture looks local. If you live in Kansas and see a beach in the photo, somethings off.
Nada, KBB, etc all use a depreciating model based on MSRP when the unit was brand new to calculate the vehicle's current value. They may claim otherwise, but if you track units like I do, you will see the formula they use. Their numbers can be skewed in one direction or another.
Assume that offer prices are a little on the high side on craigslist - negotiate hard! I check ebay for completed auctions to see what FMV is for the unit. That way you know what someone was actually willing to pay for the vehicle. They can offer any buy it now price for the unit until they are blue in the face.
Also, as stated before, be wary of vehicles that are selling for 30-40% less than the FMV price. Something is likely wrong with the car (either mechanical issues, or the vehicle was in an accident & the guy rebuilt the car).
Carfax is a joke; you need a certified inspector trained in detecting prior paint work to look at the car before you buy it. MOST ACCIDENTS are not reported to carfax. A car that was in a nasty accident may have all sorts of problems. Believe me, I know! It may also not even have any information on the title indicating salvage/rebuilt.
To the OP, you seem like you are in a lot of debt. I don't want to sound judgmental or condescending. I know you want a dependable and nicer car now. Buying a used lexus is definitely a good idea as they will hold their value. I purchased my 2005 M3 back in 2008 for 24k, and they sell for a similar price to this day (I do keep mileage low though). But if I may make a suggestion...Please pay cash for a cheaper car now. In a years time (or once you reach your debt reduction goal), then buy the nicer car. You can always sell the cheaper car a year from now and it will hold it's value pretty well. Adding another payment to the list of payments you already have will only decrease your savings rate, which will reduce your ability to knock down your debt.
FWIW, if you have low interest student loan debt, I wouldn't worry so much about that - Pay that last! It's the high interest CC debt that needs to go first. It seems like you got an awesome job that pays well, use it to destroy debt! I hope you take this in the spirit in which it was intended.