Hilton has had a price match plus an additional 25% off for a number of years. I checked the lowest price (HHonors) on the Hilton website and then shopped around. Orbitz was lower. I called Hilton and it took about 30 minutes as they check their rate and then go to the site I found to confirm the lower rate. They then match that rate and take another 25% off. It took a while as they then had to put the rate back to XPF currency as that is how the Hilton site displays the rate.

The Hilton rule is that the lower rate must be viewable and bookable by anybody. That would exclude Costco as you have to be a member.