Some of the nerdiest-looking cars in recent automotive history are making a comeback, at least in resale value, as a growing number of value-driven drivers put gas thriftiness ahead of image.

Early-1990s econoboxes such as Ford Festiva, Hyundai Excel and Geo Metro — once the punch line of jokes — have seen their used car prices climb from giveaway levels as low as $1,100 a few months ago to upward of $6,000 today, Kelley Blue Book says.

"Remember that nerds will rule the world someday," says Phil Skinner, collector-car market editor for KBB, the popular used car price-tracking service.

He says prices have risen up to 30 percent for the low-end 15-year-old jalopies.

With AAA pegging gas prices Wednesday at a record $3.758 a gallon nationwide, some of those old tin cans get gas mileage equal to today's best and pricey hybrids.

A 1993 Geo Metro XFI, a subcompact imported by General Motors, is EPA-rated at a 46 miles per gallon average. That's the same as a 2008 Toyota Prius gas-electric hybrid, which starts at $21,500.

Festiva, Excel and the others get mid-30s mpg or better on the highway. Enviable gas mileage was made possible by smaller engines: The Metro had three cylinders.

The cars were also lighter than today's models, sometimes lacking air bags and other safety features that add weight.

Experts advise taking the safety trade-off into consideration.

"What is your life worth for that extra 10 miles per gallon?" asks Jon Linkov, managing editor for autos for "Consumer Reports."

At the bottom rung of the auto industry, the little cars were usually hawked to college students and seniors.

Hyundai Excel's reliability was so spotty, for instance, that the South Korean automaker — though widely lauded by reviewers for quality in recent models — is still trying to live down its past reputation.

"They were made as disposable cars," Skinner says. "The vast majority have been sent away to the crusher."

Nick Skouteris, an Atlanta auto restorer, says he has fixed up and sold about 10 Geo Metros but is having trouble finding more at reasonable prices. He says he had his sights set on a Metro convertible on eBay a couple of weeks ago with rust holes and 175,000 miles on the odometer that went for $3,000.

"They are hot cars right now," Skouteris says. "You can't find one cheap enough."

In Los Angeles, John Chris is selling his salvaged 1988 Hyundai Excel with 115,000 miles — a great car, he insists, except for that little mishap on the 101 freeway — for $750.

"I wouldn't know about the nerdiness," Chris says. "It looks good."