Unless you have a way of producing or delivering them more cheaply than anyone else, you generally want to avoid selling parity products. A parity product is one that is no different from other products in its category. When you can't differentiate your product's benefits from the competition, you must resort either to superior marketing or to having the lowest price. (And superior marketing is difficult when you have no benefits to tout.)
A parity product resembles a commodity, which, according to Webster's, is a "mass-produced unspecialized product". Parity products are not necessarily mass produced, however.