We analyze a nonlinear economic pricing model with limited information. A seller offers a menu with a finite number n of choices to a continuum of buyers with a continuum of possible valuations. By revealing an underlying connection to quantization theory, we present the necessary conditions that the optimal finite menus for the socially efficient and for the revenue-maximizing mechanism, respectively, must satisfy. In both cases, we provide an estimate of the loss resulting from using the n-class finite menu. We show that the losses converge to zero at a rate proportional to $1/n^2$ as n becomes large. We then extend our nonlinear pricing model to the multi-product environment, where vector quantization can be used to jointly designing finite menus in multiple dimensions.