In sales, you always need people to "Buy Now!"
If you think about it, you see it all the time:
"Limited Time Offer."
"While Supplies Last."
"One Day Only."
And the list goes on.
Here's a subtle example that I stumbled across today. Not only is the conference well-priced, but the buying mechanism compels you to act sooner, lest you miss out.
Bruce Springsteen on Broadway
8 hours ago