Piston less pump for rocket has been proved to be the most economical than piston pump or turbo pump.In piston less pumps, piston is absent. It has very much less rotating parts than that of piston pumps or turbo pumps. So, it has less friction losses and there by it helps to improve the efficiency of the engine considerably.They can be easily installed in the rocket than turbo pumps. Also ,it reduces the weight of rocket. This article discusses the working , advantages of piston less pump over turbopump. Pistonless pumps are 80-90% economical than that of piston pump or turbo pumps . NASA has manufactured such kind of pump and tested it actually,and they found it works conveniently
NASA have developed a Low cost rocket fuel pump which has Comparable performance to turbo pump at 80-90% lower cost. Perhaps the most difficult barrier to entry in the liquid rocket business is the turbo pump.A turbo pump design requires a large engineering effort and is expensive to mfg. and test. Starting a turbo pump fed rocket engine is a complex process, requiring a careful of many valves and subsystems.In fact , Beale aerospace tried to avoid the issue entirely by building a huge pressure feed booster. Their booster never flew, but the engineering behind it was sound and ,if they had a low cost pump at their disposal ,they might be competing against Boeing. This pump saves up to 90% of the mass of the tanks as compared to a pressure fed system. This pump has really proved to be a boon for rockets . By this pump the rocket does not have to carry heavy load and can travel with very high speed.