cars.com is a good one and so is autotrader.com. Also, the way I found mine (going to pick it up tomorrow!) was by punching in new and used Raptors in the search function.
I thought I wanted just a new one but by looking at used also I found basically the exact truck I wanted with really low miles and a good price, thousands less. Call it an "almost new" truck.
I had a specific color and options in mind and the new 14s I looked at and contacted dealers about either were priced really high or were already sold.
Also, there is ebay, worth a look
---------- Post added at 07:28 PM ---------- Previous post was at 07:25 PM ----------
Oh, to the OP, I am not REALLY buying sight unseen. I will look at it tomorrow closely before we do the deal.
However, I believe I would buy sight unseen under certain circumstances, and with the 7 day return vehicle option