A manually operated pump including: an inlet one-way valve; a pump chamber downstream of and in fluid communication with the inlet one-way valve; a piston interior to the pump chamber and slideably engaged with the pump chamber; an actuator engaged with the piston or the pump chamber; a compression spring engaged with the actuator; and an optional outlet one-way valve downstream of and in fluid communication with the pump chamber; wherein the compression spring includes a continuous thermoplastic elastomeric tube supported between opposing offset tube supports.