The cost of purchasing a car is creeping higher as more buyers are hit with a surprise familiar to anyone who has ever bought a house or pored over a phone bill: high processing charges.

States increasingly are passing laws that let car dealers raise the fees they charge for preparing and processing all the paperwork involved in closing a deal on a vehicle, including documents for registration, vehicle titles and license plates.

Paperwork charges can now run as high as $900 in the roughly 30 states without set fees or caps on fees. The fees, often called "doc" or documentary fees, now average $400 to $700 in those states, according to estimates by automobile club AAA, compared with averaging less than $200 five years ago. In some states, the fees also can be subject to sales tax.

A new law in Ohio lets dealers charge as much as $250 for doing the paperwork, up from the previous limit of $100. In California, a bill signed into law last week raises the limit to $55 from $45 for dealers in the state, starting in January. Limits on paperwork-processing fees have also been raised or set in recent years in Michigan, Washington and Maryland, where the doc fee maximum has climbed to $100 from $25. Earlier this year in Florida, where there is no cap, documentary fees rose to $599 from $549 at South Florida outlets of national dealer chain AutoNation Inc., the first increase in five years. Similarly, in Georgia, Mercedes-Benz of Augusta added a doc fee of $599 last year, up from $499. Many dealers in the Las Vegas area charge processing fees of around $400, compared with fees in the area around $200 roughly a decade ago.

Consumers and lawmakers in some cases are fighting the auto fees. Class-action lawsuits are pending in states such as Arkansas and Florida. A number of states from Alaska to New Jersey, meanwhile, have introduced legislation in recent years that challenges, seeks to limit or requires disclosure of such fees.

The higher fees come as major turmoil in the car industry has meant thinner profit margins on new cars for dealers. Efforts by Detroit auto makers to spur sales by offering deep discounts and making sticker prices closer to the final price of the car have cut into dealer profits. And dealer profits may get even slimmer in coming months as some car makers try to clear out 2006 models from overflowing lots with buying incentives this fall and lower sticker prices on new models.

Domestic car makers also are trying to wean themselves off deep discounts by cutting production. DaimlerChrysler AG Chairman and Chief Executive Officer Dieter Zetsche last month said Chrysler would cut retail-vehicle production for the third and fourth quarters, and Ford Motor Co. announced plans to close factories and cut jobs. The smaller profit margins have led many dealers to look to areas such as service and parts and contract fees for extra revenue.

Net profit on average for dealers per new vehicle was $60 last year, down from $172 in 2004, according to the National Automobile Dealers Association. "This is a way to try to make another $400 or $500 on the sale of a car," says John Nielsen, director of the AAA Auto Repair Network, who says he has noticed the doc fees becoming more widespread in recent years.

Teresa Tucker says she was charged a nearly $400 paperwork processing fee even though she bought her red Mini Cooper S convertible out of state and handled financing, getting a title and registering the vehicle herself. "I wish I made $400 for that much work. It was a rip-off," says the 41-year-old construction estimator in Pelham, Ala.

Car dealers say they have boosted fees largely because new federal and state rules have led to more paperwork requirements over the past five years. Federal laws adding additional paperwork requirements include Gramm-Leach-Bliley Act privacy requirements that dealers create a plan for safeguarding customers' private information and train staff to implement it. Dealers are also placing more emphasis on certain national-security requirements required by law like checking customers against federal lists of people suspected of supporting terrorist activities and documenting that the check was done.

Besides the new requirements, doc fees generally cover the time and manpower required to process documents for trade-ins, titles and registrations. In some states, the fees also include the costs of prepping a vehicle like cleaning and inspecting it.

In California, meanwhile, the $10 increase was a compromise between pro-consumer and pro-dealer legislators worked out to pass the state's Car Buyer's Bill of Rights law, which took effect in July. The new fee is meant to cover the cost of processing additional documents that the law requires such as an inspection report for certified-used vehicles and reports of monthly costs to purchase a car with certain items or without, says Brian Maas, director of government affairs with the California Motor Car Dealers Association.

Dealers generally charge the same fee to every customer regardless of whether they are out of state, in state, buying used or buying new, leasing or financing. This is because some deals turn out to be simple and involve little paperwork, while others can be more complicated with lost titles or lots of paperwork, but there is little way to determine ahead of time what the paperwork for a certain deal will cost. "You have to make the fee uniform across the board," says Charles Anderson, new-car sales manager at Land Rover Las Vegas, which charges all buyers a $399 "doc fee."

In many states without set caps, there is little regulation of the fees besides statutes or attorney general opinions specifying that the fees are allowed or should be disclosed in sales contracts and advertising as separate from government fees and as a separate line item. But not all states even require such disclosure and consumer advocates argue that the fees sometimes aren't in line with the cost of the work dealers are actually doing.

Consumer advocates say in many cases car buyers aren't aware of the fees even though they are listed on the closing documents, and don't consider them a part of negotiations. Dealers sometimes may also initially quote a low price that doesn't include the fees, meaning that car buyers find out about the added fees only as the deal is being completed.

Car buyers always have the option to negotiate the fees, ask for added car features in exchange for paying them or, if a dealer isn't willing to negotiate, walk away and shop elsewhere.