Her home was fine. But once the power is turned back on, how is she going to pay the utility company after shelling out for the food and water stockpiled when she fled Hurricane Gustav and paying more than $3 a gallon for gasoline?

"This is bill money," the woman, who declined to give her name, said as she fought back tears. She was standing in line at a Walgreens drug store Wednesday after returning to her home in St. Bernard Parish. "If you're living from month to month, when the bills come, you can't tell Entergy, 'I spent it on evacuating."'

Darleen Crane, 67, and three relatives drove from suburban Metairie to Tuscaloosa, Ala., in two cars. They spent two nights in a hotel at a total cost of $250. Gasoline cost about the same. Add another $200 for batteries, flashlights, hand sanitizer and other supplies and her estimated total cost was around $700.

Close to 2 million people fled Gustav in coastal Louisiana. About 18,000 from New Orleans availed themselves of free bus and train transportation to public shelters. But even those people had costs: Roxie Raymond, 23, of Raceland, La., estimates that the evacuation cost her about $1,200 in lost wages and spoiled food in her refrigerator. "I feel depressed and frustrated," Raymond said in an interview at a shelter in Fort Worth, Texas.

Evacuees may be able to recover some costs if they register with the Federal Emergency Management Agency, but it was unclear Wednesday exactly what will be covered.

Denise Everhart, a FEMA spokeswoman, said some hotel stays for people who are unable to return home for an extended or indeterminate time may be covered by FEMA. But the dates covered had not been determined as of Wednesday night and it was unclear whether the program would include those who evacuated for a short time and came back to undamaged homes.

Also unclear was whether food and fuel costs evacuees incurred while on the road would be covered under a recent presidential disaster declaration. Everhart and FEMA spokesman Manuel Broussard both stressed that, until the determination is made, it is important for those who left town to keep receipts for their expenses.

"The receipts are an essential element," Broussard said. "When they apply, they're going to have to document that they did evacuate, that they did stay in a hotel."

Also, they should register now with FEMA by calling 1-800-FEMA or visiting www.fema.gov.

Robert Hartwig, president of the industry-funded Insurance Information Institute in New York, said homeowner insurance policies typically don't cover evacuation costs like gas and hotel rooms. But he said residents should save their receipts in case certain expenses can qualify as "temporary living expenses" covered by a policy.

Bob Warzeski, a teacher from New Orleans who evacuated to Tennessee with his wife, Glenny, said they spent about $200 in gasoline and food. "We stayed with relatives so we saved an enormous cost there," he said.

But there are other costs. "Staying with relatives is kind of disruptive of their routines. It's stressful on the people you're staying with."

Will such costs dissuade people from evacuating for future storms?

Jay Baker, a Florida State University professor who studies natural and technological hazards, notes people in Panama City, Fla., evacuated three times -- in roughly the same percentages each time -- during the 1985 hurricane season.

Susan Cutter, director of the Hazards Research Lab at the University of South Carolina, is optimistic people will use good judgment. "The people of New Orleans have had experience with not evacuating," she said Wednesday, referring to the thousands stranded in 2005 by Hurricane Katrina. "The alternative is to endure a little stress, endure a little expense and get out of town."

Crane didn't like the $700 cost or the stress of her 11-hour trek to Tuscaloosa. But she doesn't regret leaving. "You don't know what these crazy storms are going to do."