According to Hustler it is not that expensive. http://www.hustlerturf.com/zeon.html Just think of all the things that would go away with this mower. Gas, gas filter, air filter, oil, oil filter, hydro fluid, hydro filter, spark plugs, belts, carb problems, starter problems, pto problems, noise, emmissions, engine heat, fire hazard. It seems like I could go on and on. If you could replace the batteries individually (which I think you can) it would seem cheap compared to all the stuff that goes with a gas mower. I have had a commercial gas engine that started leaking oil everywhere at 350 hrs.