[fjtorres]

Sony allows discounts. They try to minimize them on consoles and TVs (not too successfully on the latter) but everything else is fair game.

Apple, on the other hand, practices a different strategy that isn't classic price maintenance.
Instead of discounts, they offer up low-spec versions of their products so they can offer lower price points and then upsell the consumer on a slightly more useful (and expensive) version. Want a $100 iPod? You can have it. It won't be comparable to the full iPod touch but it's an iPod. Same thing with keeping the iPad2 around so long. It gave them a cheap iPad to fend off the androids. It works beautifully because a lot of their customers are looking to buy the brand or buy into the ecosystem rather than a specific feature set.

There's more to modern retailing than just discounting or price fixing.
A vast middle ground toolkit of sophisticated moves is available to both vendors and retailers savvy enough to exploit them.

If you look at the pricing of the XBOX 360 over the past 8 years you'll find that as Sony was trimming features of the PS3 to get pricing in line with buyer expectations, Microsoft actually raised their average selling price *twice* while dropping their advertised pricing, all through upselling consumers.
Even now that you can get a 360 for as low as $149, the bulk of the units are selling for $249 and $299.

Consumer product retail pricing is an art Apple and Amazon and Wal-Mart all excel at in different ways. Microsoft is good and getting better but still not top tier.

Publishers? Not so much. Putting a gun to the buyer's head doesn't buy you many friends.