I'm always automatically skeptical about limited-time-offer sales pressure. The harder the advertiser/salesman tries to push a product in my face, the more suspicious I become.
"Buy it now because it'll go up in price soon!", "but for a limited time - today only - it's on sale at a special discount", "buy it now, before they're all gone!", etc.
If demand for the product is higher than supply, it's selling like crazy, and it's an unbelievably fantastic bargain at this price ... why don't they increase the supply or bump the price (profit) up a notch? It's not like manufacturers and vendors are all magnanimous or running a charity. And it's not like they'll say "ah, well we finally sold all 10,000 units, sorry people there's no more because we're moving on to another product".
I know advertisers are trying to hit you where you're psychologically weak, hype up your interest in the product ... but do they really have to make it so obvious? Does this **** actually work often enough on consumer sheep that they don't even have to think of new tactics?