It's also fine to occasionally pay full price for clothes, if the item in question will be a wardrobe staple.
It's hard to go wrong with a good pair of black pants. They're like jeans; versatile, plus they come in every cut and style, so everyone can find a pair. These are the ones I've been wearing for almost a decade: the Editor Premiere Stretch from Express. This particular pair is $59.50, though the Editor umbrella covers prices from $49.50 to $88. Even at full price, they're not expensive, but if you still CANNOT fathom shopping when there isn't a sale, know they get marked down a few times a year, usually buy one get one half off. In fact, that's happening now! How perfect.
Like their denim counterparts, the Editor dress pants come in three lengths, 30", 33" and the blessed 35". (NOTE: if you put them in the dryer they WILL shrink, so learn from my mistake.) If you avoid zapping them into floods, they'll last you a long time. Like, years, providing you're not in the middle of a growth spurt.
They're worth the investment. I wouldn't wear bad pants for 10 years. Trust me.