A hand operated dispensing pump made from all plastic materials, for dispensing fluid from a container, comprising: an actuator, a chaplet, a stem, a piston, a pump body, a check valve, and an elastic polymer spring; the actuator including a flow passage having an inlet and an outlet; the stem including a flow passage having an inlet and an outlet; the pump body formed as a generally hollow, cylindrical body, having an open upper end, a fluid inlet at a lower end, and an interior volume therebetween; the check valve formed integrally with the pump body and disposed at the lower end and above the fluid inlet of the pump body; the stem configured such that the piston is attached to the inlet of the stem; the piston configured to be slidable downwardly on the stem to close the inlet of the flow passage of the stem and configured to be slidable upwardly on the stem to open the inlet of the flow passage of the stem; the chaplet configured to be disposed within the open upper end of the pump body; the stem configured to be disposed via guide means within the chaplet; the piston configured to slidably engage an interior cylindrical wall of the pump body and seal against the interior wall of the pump body; at least one lower vent in the pump body in air communication with the interior of the container, wherein the lower vent is blocked by the piston when the piston is in a rest position and unblocked during a down-stroke of the piston; the flow passage of the actuator configured to be in fluid communication with the flow passage of the stem, the flow passage of the stem configured to be in fluid communication with the interior volume of the pump body, the interior volume of the pump body configured to be in fluid communication with a product to be dispensed; wherein the elastic polymer spring is dome shaped and has a wall thickness (128, 130) that tapers from a bottom of the spring to a top of the spring, and is_configured to drive the actuator to a rest position; wherein, upon a down-stroke of the actuator, the check valve closes the fluid inlet of the pump body and the piston slides upwardly and sealing on the stem opening the inlet of the flow passage of the stem; and wherein, upon an up-stroke of the actuator, the check valve opens the fluid inlet of the pump body and the piston slides downwardly on the stem closing the inlet of the flow passage of the stem. an actuator, a chaplet, a stem, a piston, a pump body, a check valve, and an elastic polymer spring; the actuator including a flow passage having an inlet and an outlet; the stem including a flow passage having an inlet and an outlet; the pump body formed as a generally hollow, cylindrical body, having an open upper end, a fluid inlet at a lower end, and an interior volume therebetween; the check valve formed integrally with the pump body and disposed at the lower end and above the fluid inlet of the pump body; the stem configured such that the piston is attached to the inlet of the stem; the piston configured to be slidable downwardly on the stem to close the inlet of the flow passage of the stem and configured to be slidable upwardly on the stem to open the inlet of the flow passage of the stem; the chaplet configured to be disposed within the open upper end of the pump body; the stem configured to be disposed via guide means within the chaplet; the piston configured to slidably engage an interior cylindrical wall of the pump body and seal against the interior wall of the pump body; at least one lower vent in the pump body in air communication with the interior of the container, wherein the lower vent is blocked by the piston when the piston is in a rest position and unblocked during a down-stroke of the piston; the flow passage of the actuator configured to be in fluid communication with the flow passage of the stem, the flow passage of the stem configured to be in fluid communication with the interior volume of the pump body, the interior volume of the pump body configured to be in fluid communication with a product to be dispensed; wherein the elastic polymer spring is dome shaped and has a wall thickness (128, 130) that tapers from a bottom of the spring to a top of the spring, and is_configured to drive the actuator to a rest position; wherein, upon a down-stroke of the actuator, the check valve closes the fluid inlet of the pump body and the piston slides upwardly and sealing on the stem opening the inlet of the flow passage of the stem; and wherein, upon an up-stroke of the actuator, the check valve opens the fluid inlet of the pump body and the piston slides downwardly on the stem closing the inlet of the flow passage of the stem.