means A pricing strategy where goods cost $X.99 instead of $X, tricking customers into perceiving the price as dramatically lower than it actually is because people process the leftmost digit first and anchor there.

from Emerged in mid-1800s retail when department stores discovered customers read prices left-to-right, not holistically. The .99 became ubiquitous after 1950s supermarkets realized it reduced price resistance by exploiting cognitive shortcuts—your brain sees $5.99 and registers $5 before registering the 99 cents, creating an illusion of restraint.