What state do you live in? In Oregon there is also a $1500 credit. Colorado is very generous with a credit of $3,285. Other places allow use of HOV lanes. There are other benefits out there.

You maintenance with a Prius will be much lower. Probably in excess of $3000 in savings over the life of the vehicle, if not more. Brake shoes don't wear out. The engine is never stressed, lots of reasons.

The Prius is very relaxing to drive and quiet. The continuous variable transmission is sweet. What is quality of life worth?

In comparing vehicles for MPG, I just use the differential between the EPA numbers. Why? Because if you can nurse great milage out of a Corolla, you will do the same with a Prius. Although some people actually improve with the Prius due to the instant feedback from the trip monitor that shows what the current MPG is on a running basis.

Should you ever need to sell, the resale value of the Prius will be clearly better than the Corolla, especially 5 years from now when hybrids with 50+ milage will hopefully be the norm.