4wd RAV-4, with 22 mpg, cost $19,000 (the 2003 price I would have paid to replace the RAV-4 new), while the Prius, with 50 mpg, cost $22,000. So the cost difference was $3,000 on the table right then, in favor of the RAV-4.
The gas mileage difference between the two cars is roughly half... Consider the price I paid for gas recently vs. the price I paid when I first got the Prius has basically doubled in those three years. Waving my hands, I would say that I've paid roughly $3,000 less in gas over the three years I've had the Prius. And at today's prices, I would pay $2,600 more for one year of gas for the RAV-4 than the Prius.
I am already at gas-cost win in three years. When I bought the Prius, the marketing pitch was a make-back/break even in approx. six years. Inflation sucks. But my Prius makes me happy (when it's not trying to kill me).
ETA: Ok, it's been pointed out that I never mentioned how many miles I drive. My Prius just had its third birthday, and it has