I've done this a few times at Best Buy. First time was with my flat screen HD tv, bought it a Best Buy and 10 days later Amazon had the same set for $300 less. Took in the amazon print out and argued with a manager at Best Buy, got the credit. This most recent time, I priced out the PS3 on the...
I printed out the dell cart with the PS3 in it, and both codes applied. Took the print out to Best Buy and they price matched, plus 10% of the difference.