Notably, these are price matches. That means a) you have to ask for them, b) you need to prove Walmart's pricing, despite it being widely publicized, by showing it via a printout or a webpage display on your smartphone or tablet.
Not only was this price matching policy reported online, we confirmed it ourselves via a F2F talk to an Apple representative at the Apple store at the Hillsdale Mall in Northern California on Friday. They also confirmed the requirement of "some sort of proof."
It will probably be OK if that proof is a Staples website image (as shown) instead of Walmart's, as Staples is not price matching Walmart, but instead is pricing their 16GB WiFi-only version at the same $479 price, and advertising it as well.
That's another thing: since Apple and Best Buy are price-matching, you won't find the lower price on their online stores. You will have to head to a physical retail outlet to receive the $20 discount.
Speaking of visiting an Apple retail store, we visited one ourselves on Friday. There was a very small line at 8 a.m., and we overheard an employee saying the line was less than expected. It was underwhelming, and the online reception is just as underwhelming, based on recent launches.
At the time of this writing, 10:30 a.m. PT on Friday, only one iPad version, the T-Mobile 128GB version, shows a delay in shipping. That version won't "ship" for 5-10 days, while all the others currently say they will be delivered on Nov. 4.