Hilleberg is one of a few companies that prohibit retailers from discounting prices. Retailers can have their distribution rights pulled if they violate that agreement. I've had conversations with a few independent (ie non-chain) retailers and what that boils down to is that they cannot advertise at a discounted price. So for example, a store wide discount coupon, if widely promoted, usually excludes brands like Hilleberg.
But in reality, it's up to the retailer to decide whether they will discount without promoting it. I've walked in to a store wide sale where Hilleberg was specifically excluded in the advertising, but I've seen a small number of their tents discounted in-store. It's really hit-or-miss, and I'd say your best chance will be with independent brick and mortar retailers.
Have you looked at the Special Offers page on Hilleberg's US web page?