I do not know about Prius but Honda insight is a very simple car.You can forget about its electric part an use as an conventional car.No extra cost for electric part , its platform is identical to Honda city so the mechanical parts are cheaper than the civics. Other thing is, if some thing happens to the electric part you can switch it off then it will work as a 1300cc conventional car. However it has become the most reliable car in US market in 2010 as there was no retorted problems