Remarkably accurate advice by the experienced buyers on the forum.
Here are my observations from my truck buying efforts in December:
1) tried the Costco system, and with very few dealerships in this area that were on their list, I was limited to one at which I didn't feel that they were honoring the price or showing me the invoice as required, so bought elsewhere at significant savings off the Costco number
2)start at the invoice price, that you can learn from various websites before getting to the dealership, then go down from invoice. Your goal is to get to a price that gets into the "holdback", a term that means the amount the dealer gets back from the manufacturer at the end of each quarter. Here's an example: MSRP is $35,000, invoice is $31,000, incentives/rebates are $2000--now you're at $29,000. The dealer will still make a profit on the $1200 holdback they will see eventually. This dealer split the holdback with me, for even more off. (not my actual numbers, by the way).
3) one last thing I was told is that when dealers do a dealer swap to get your special car from another dealer, that the holdback stays with the dealer who ordered the car, so your dealer can't offer you as low a price compared to one they own.