NEW YORK (MainStreet) — The fallout from the Moore, Okla., tornado is measured first in lives, with 24 people killed (many of them schoolchildren), 237 injured and 13,000 homes damaged by the killer twister.

But the financial toll is a heavy one, too. Insurance analysts estimate that the tornado will wind up costing $2 billion in damages.

For Oklahoma residents struggling to deal with the tornado's aftermath, that burden grows heavier if you're not diligent about avoiding disaster-related scams.

"It's unfortunate that there are people out there trying to cheat others out of their hard-earned money under the guise of providing a service after a disaster," says John Doak, Oklahoma State Insurance Commissioner. "Yet it happens time and time again to unsuspecting homeowners."

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The commission has some advice on avoiding scams for state residents reeling from tornado damage.

The gist is this: Vet everything and everyone, and don't sign on the bottom line until you're sure you're dealing with a licensed professional, be it a contractor, insurance agent or financial services company.

Take your time. Rushing to ink a contract with a contractor or storm damage company isn't a wise move. Make sure to get written estimates and read them thoroughly. Don't act until you're sure you're getting a square deal.

Resist the urge to spend a lot of cash. Unscrupulous contractors may push you to make expensive repairs even on temporary repairs common after a tornado. Don't fall for it. "While immediate repairs are required to prevent further losses and mitigate damages, the costs must be reasonable," the agency says. "Your insurance company will reimburse you for the temporary repair costs, dollar for dollar, as long as the costs are within reason and you can provide receipts."

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Vet everybody working on your behalf. Make sure you check out any roofer, builder or contractor working on your home. The Better Business Bureau is a great place to start. Also, demand references from contractors. Companies unwilling to provide them should be avoided.

No down payments. One favored tactic from fraudsters is to ask for money upfront, then disappear without a lick of work being done. Always get that written estimate, and don't pay until the work is done.

The agency also advises taking a pass on "door-to-door" salesman looking to fix your house, lend you money (after a fat down payment) or provide other post-disaster services. Always work directly with your insurance company, especially when it comes to working with an insurance adjuster. The commission says you can save up to 20% on your total claim by using the insurance company's adjuster.

Also, save every storm-related receipt you have, and keep those receipt in an easily-accessible, safe place. And don't make any permanent repairs until an insurance adjuster has been to your home and has provided a financial estimate of the damage. You could be liable if the repair costs more than the estimate.

— By Brian O'Connell