Unfortunately, perfumes, and niche particularly, never go on sale in dept stores or regular stores. Occasionally, some dept stores give you points or the like when buying something, but they don't discount the frags per se. And it is really hard to find niche frag at discounters or the like.
While niche is expensive, there are some niche brands that are not especially so, that is, they are just a bit more expensive than mainstream and start at about $85-90 for 50ml. These include brands like Diptyque, Artisan Parfumeur, Etat libre d'Orange, Knize, and CDG, which can be just as good as other more expensive niche brands. Amouage unfortunately is on the high side of niche pricing.