But even the fast political action on the package - it took barely a week to negotiate - may not be fast enough to help the economy over the next several months. The first of the 117 million checks won't be in the mail until late May; some won't arrive until early August. And the shot in the arm for the economy does not directly address the problems of the sagging housing market, towering consumer debt, teetering mortgages and capital-short banks.

''If someone could build the most appropriate stimulus package it wouldn't be what we got today, but this comes close enough given the realities of the political situation,'' said Mark Zandi, chief economist of Moody's Economy.com, a consulting firm. Still, he added, ''This doesn't solve the fundamental problem plaguing the economy.''

Stock and commodity markets generally were heartened by the package. Despite a 2.2 percent drop in the sales of existing U.S. homes announced Thursday, the stock markets were up that day (though down on Friday). Despite an increase in crude oil and gasoline inventories, crude oil prices jumped back to near $90 a barrel on expectations that a stronger economy would boost consumption of petroleum products.

The stimulus package would send checks to anyone who earned at least $3,000, and as much as $600 for an individual and $1,200 for a couple, with more children. But the benefits phase out; individuals with more than $87,000 a year of income and joint filers with more than $175,000 of adjusted gross income get nothing.

Economists praised the compromise for including $35 billion for 28 million of the working poor, who are most likely to spend the money, and excluding the top wage earners, who don't need the extra cash.

''This is pumping a lot of money into the pockets of people who are likely to spend it and spend it quickly,'' said Robert Reischauer, president of the Urban Institute.

On a broader front, Douglas Elmendorf, senior fellow at the Brookings Institution, estimated that 2008 growth in gross domestic product will be 0.7 percentage points higher than it would have been without the stimulus deal.

But many analysts, state governments and business people were disappointed. Democrats had sought a boost in the food stamp program and an extension of unemployment insurance benefits, which they said would find their way into the economy faster.

A study by Zandi estimates that every dollar put into the food stamp program produces a $1.73 increase in the economy as the money is spent and spent again. By contrast, every dollar put into the business tax breaks that are in the stimulus package will increase the economy by 27 cents, according to the study. The business portion of the stimulus package allows companies to write off 50 percent of the cost of equipment in the year of purchase. This will help firms that sell long-lasting equipment such as machine tools, aircraft, and agricultural and construction equipment. Technology firms could also benefit. But much of that investment would have happened anyway, according to some economists.

Retailers will get a boost, too, not because of business tax breaks but because of consumer spending. Two-thirds of the money in rebate checks sent to spark the economy after the Sept. 11, 2001, attacks was spent within six months.

But many business people had hoped for other provisions that they say would have provided a longer-term boost to the economy. Renewable energy advocates had sought an extension of tax credits for wind and solar; those credits expire at the end of this year and they say that new projects could soon start to slow down because of uncertainty about the fate of the credits.

''It is all incredibly short term,'' said Jonathan Rose, a leading real estate developer in New York City who favors money for infrastructure projects. ''The current stimulus plan is to get checks in peoples' pockets in the hope that they'll spend it as soon as possible. That's not a strategy for sustainable investment.''

Many state governments are also unhappy with the stimulus package. By giving businesses $40 billion in tax breaks such as accelerated depreciation for equipment, the stimulus package hurts about 30 states that calculate their state corporate taxes as a percentage of federal corporate tax receipts.

Dan Gerlach, a fiscal adviser to North Carolina Gov. Mike Easley, said that the state would lose more than $300 million in revenue, a setback for a state that has strived to get out of a deficit in 2002 and maintain a modest surplus. Gerlach said the money lost as a result of the stimulus package would be equal to a 6 percent of the pay of the state's teachers, or 20 percent of the state's gasoline tax receipts, or 0.25 percentage points in the sales tax.

The stimulus package does take aim at the problems in the mortgage markets. A provision to let the Federal Housing Administration insure more subprime loans could help hundreds of thousands of people now facing foreclosure to refinance. The provision letting the government-sponsored housing finance companies, Fannie Mae and Freddie Mac, buy bigger ''jumbo'' loans should help housing markets with high values, especially in the Northeast and West Coast.

Some economists still question the need for any stimulus at all. ''Given where the economy is right now and the best forecasts of where it is heading, the fiscal package seems unnecessary as a short-run measure, while in the long run adding to the debt burden without doing anything to improve incentives for economic growth,'' N. Gregory Mankiw, a Harvard University professor and former chairman of President Bush's Council of Economic Advisers, wrote on his blog last week.

Experts who counsel low-income earners say they have mixed feelings about policymakers' hopes that people will quickly spend the checks from the stimulus plan. Gail Cunningham, spokesman for the National Foundation for Credit Counseling and a 22-year veteran of giving advice to the credit-weary poor, says she advises people to save and pay down credit card debts instead of spending more.

"It's very interesting to me that what's good for the economy could be bad for the consumer.''