Fuel consumption of hybrid cars
Size-wise (not engine-wise; the point of hybrids is that they have smaller petrol engines) Toyota compares the hybrid Prius to its regular Camry. In tests carried out for the Australian Green Vehicle Guide, the fuel consumption in the standard combined city/highway test cycle for the Prius was just 3.9L/100km; the automatic 2.5L version of the Camry uses 7.8L/100km. The Honda Civic Hybrid uses 4.4L/100km, and the comparable non-hybrid Honda Civic, the manual Si sedan, uses 6.9L/100km.
So one thing is clear – if you drive a hybrid you'll be filling up less often.