Thomas Gross leased a Toyota Sequoia last year, which was fine until his job as an ice hockey trainer changed and he began logging an extra 1,500 miles per month on the sport-utility vehicle. Suddenly, he was paying $70 more a week for gas.

"It was like every other day I was filling up," said the 32-year-old from Oceanside, N.Y. "It was a nightmare."

But Gross still had four years to go on his lease and escaping it early would cost $7,000. So he posted his lease online at LeaseTrader.com, which matches drivers wanting out of leases and those seeking one. Within four days Gross found someone who lived 10 miles away to assume his lease. His cost: $600.

Millions of consumers lease vehicles each year so it's not surprising that some might have a change of heart or circumstance and want out. Consumers for years have been able to find someone to assume their lease provided the leasing company permitted it.

But the job of finding a replacement is a lot easier these days with the help of a few Internet companies that have sprung up since the late 1990s.

"What we offer more than anything is a way out of a contract," said Sergio Stiberman, who founded LeaseTrader.com in 1998 when he wanted to escape his lease.

Last year the Miami-based company handled 20,000 lease transfers and expects to conduct 35,000 this year.

Basically, sellers pitch their leases online to prospective buyers. Sellers and buyers negotiate by phone or e-mail. The leasing company conducts a credit check on the buyer and has the final say on whether a deal goes through or not.

About 90 percent of leasing companies allow customers to transfer their lease, said Scot Hall, executive vice president of operations for Swapalease.com in Cincinnati, the other significant player in the market. And about 20 percent of those require the person who originally took out the lease to remain on it, putting that person on the hook in case the individual assuming the lease fails to make payments, Hall said. This rarely happens, he added.

LeaseTrader charges customers $80 to list online until their lease is transferred.

Prospective buyers pay $40 for a 60-day membership, which includes a preliminary credit check. Sellers and buyers each pay a brokerage fee to LeaseTrader of $150 or $250, depending on the services included.

Swapalease's standard package costs sellers $50 to list on the site, plus another $95 if a match is found. Fees for buyers start at $35 for a 45-day membership.

Other fees come into play. Those considering a lease in another state may want to hire an inspector to check out the car in person. LeaseTrader charges $199 for this service; Swapalease charges $99.

A leasing company will charge a lease-transfer fee that can range from $35 to $600, Stiberman said. And there are shipping fees to deliver far-away vehicles.

Sellers sometimes offer incentives to make their lease more attractive, such as helping with shipping or transfer fees, or giving cash that can be applied to monthly payments.

Because buyers will assume the obligations of the terms of the lease they need to make sure they know what fees and responsibilities they are taking on.

"We strongly recommend buyers to obtain a copy of the original contract so there are no surprises," Hall says.

"A good deal can be found," said Alex Rosten, an auto industry analyst with Edmunds.com. "Pay very close attention to the transfer fees and the requirements. If you don't have very good credit you won't be able to take over the lease."

Rosten tried to assume a lease through LeaseTrader about five years ago but the leasing company gave him the thumbs down because he didn't have a long enough credit history. He didn't receive a refund of the $150 brokerage fee. (LeaseTrader has since started its own credit verification before buyers and sellers start negotiating.)

Gary Phillips, operations manager at Allstate Leasing Inc. in Owings Mills, Md., said the sites might fill a niche, and Allstate would have no problem if its customers found a qualified person to take over a lease online. But Allstate also requires the person who originally took out the lease to remain liable for payments.

Randall McCathren, a consultant to the vehicle leasing industry, suggests that consumers might come out ahead financially by taking out their own lease on a used car rather than assuming someone else's.

Gross, the hockey trainer, disagrees. By assuming someone else's lease you can avoid hefty upfront fees, including taxes, he said. He plans on using LeaseTrader again, this time to assume someone else's lease.

Eileen Ambrose is a columnist for The Baltimore Sun, a Tribune Co. newspaper.