Gas at my cheapo New Jersey service station is edging up to $2 a gallon again, thanks to $50-a-barrel oil. And my 9-year-old Sable wagon is in the shop once more, this time for a new brake line.

Events like these make you think about the joys of owning a new vehicle – one with great gas mileage.

But for that second car … well, maybe some dinky gas-saver would be worth a look.

Just how much COULD you save?

The current gas-economy champion is the Honda Insight. According to a Web site run by the Environmental Protection Agency, http://www.fueleconomy.gov/, this gas-electric hybrid gets 60 miles to the gallon in the city, 66 miles on the highway.

Assume I’d drive it 12,000 miles a year, mostly around town. At 60 miles a gallon, that’s 200 gallons a year.

At $2 a gallon, I’d pay a mere $400 a year for fuel.

Compare that to an SUV such as the Land Rover Discovery, rated the least efficient SUV by the EPA. It gets 12 miles a gallon in the city, or 1,000 gallons for the same trips to the grocery store and soccer fields I’d make in the Honda. That’s $2,000 a year.

OK, so maybe it’s worth an extra $1,600 a year for the comfort, safety and status of a fancy SUV. (Not for me, but perhaps for you.)

Still, that adds up.

It’s $8,000 over five years, $32,000 if you keep it up over 20. And I’m just getting started. What if you were to buy the Honda and invest the fuel savings, which come to $133.33 per month?

Put it into a good stock fund and make an average of 7 percent a year and you’d have $69,500 after 20 years, enough to let you retire a year or two early.

But wait! There’s more.

The Honda goes for about $20,000, the Land Rover for about $40,000.

If you took out a five-year, zero down loan at a typical rate today of 5.8 percent, payments on the Land Rover would be about $770 a month. The Honda would cost just $385 a month.

Let’s assume you always buy the cheaper car and invest a $385-per-month savings for 20 years. At a 7 percent return, that would grow to slightly more than $200,000.

Added to your gas savings, you’re now ahead by nearly $270,000.

On top of that, you’d probably pay a lot less to insure the cheaper vehicle, and repair costs would probably be smaller. Maybe you’d be ahead by $300,000, perhaps more.

Of course, in real life you’re not going to get exactly this number. You’d have to figure the turn-in value of each vehicle and the replacement cost, look at inflation and taxes on your investment gains.

But there’s no disputing the fact that choosing smaller, cheaper, fuel-efficient models would save you a fortune over time.

So, what will I do when my old Sable comes out of the shop? Keep it, probably.But someday that Sable will die. And then a gas-electric hybrid will surely find its way to my driveway.

I can hardly wait.