wtf?
From Amazon.com:
I'm still no clearer on why they don't actually display the price, particularly since the "too low to display" figure is $629.87.
Price "Too Low to Display" Explained
The "too low to display" message indicates an additional discount is in effect, and this discount is calculated in the Shopping Cart. You can see this price by clicking the product name and then selecting the Add to Cart button on the product information page. Please be assured that simply adding an item to your cart does not obligate you to buy it--you can always delete the item from your cart if you decide not to purchase it.
I'm still no clearer on why they don't actually display the price, particularly since the "too low to display" figure is $629.87.

no subject
When you're a certified reseller, you're authorized to retail the products. You're under a contract: Thou shalt not scalp other authorized resellers, thou shalt participate in promotional programs, thou shalt honor our warranty, as well as more obscure terms, such as thou shalt not sell mail-order from a brick-and-mortar storefront, and thou shalt move /n/ amount of product per year to sustain authorized status.
'Price too low to print' usually means, 'We're selling this below the manufacturer's allowed price range.' Sometimes it means, 'We're selling this outside our permitted sales territory,' but I assume that Canon would not be restricting Amazon (or its partners, usually Adray and J&R for camera gear in the States) to an arbitrary region.
When you see a retailer promoting a product marked noticeably lower (or higher) than the median price (such as $150 for an iPod), they typically purchased it through a wholesaler who isn't bound to reseller contracts. The reason why manufacturers require you to supply purchase information when registering a warranty on hardware is, aside from selling you to direct mail marketers, is so that they can decline warranty support if you didn't purchase through the appropriate channels.