Best Buy doesn't typically pricematch Warehouse stores like Costco and Sam's. The reason being is that you have to pay a yearly fee to those places to get their "membership" prices. On top of that, Costco and Sams (at least the couple near me) don't do over the phone price quoting, and they don't let you take a photocopy of the price tag, with the price, out of the store.
How do I know this? Because last year, I saw a 36" Toshiba HDTV at Costco for $1500, and at Best Buy for $1900. We wanted to get a price match, so we asked what would happen if we had Best Buy call to confirm their price. They said that they aren't allowed to do that, "corporate policy". So, we then asked them to photocopy the price tag for us. They said they could do it, but would have to block out the price. Again, "corporate policy". So, we took it and hand wrote the price on there. We went over to Best Buy and showed them the tag. They said that they aren't supposed to pricematch Sam's Club and Costco, but since we were also going to get the 4 year service plan, they'd make an exception. Also, they only matched the exact price, instead of +10% the difference, since they were "making an exception".
So we got the TV, and two days later cancelled the service plan.
We also later found out the reason why Costco was so much cheaper was because the TV was a slightly different model.