SAN FRANCISCO (MarketWatch) -- The question most Americans want answered about the economic stimulus plan is simple: What's in it for me?

Well, if you're an average working American with no kids in college and not looking to buy a new home or car, the answer is about $1,000 over the next two years. Double that if you're married and you and your spouse work; shrink it to $300 if you are retired or disabled. And get out your calculator if you are unemployed.

It's not a lot of money to cheer about, but then again, you set aside $500 for every working American, and the figure for tax relief is going to start around $140 billion right there; the sheer size of the project dictates that getting a few thousand bucks per family would be too much to handle. And anyway, the stimulus bill's main focus is shoring up the economy through job creation and aid to states.

Still, there are some tax provisions in each of the House and Senate versions of the stimulus plan that may benefit you. "There are a lot of little things covered from a tax standpoint," said Mel Schwarz, director of tax legislative affairs at Grant Thornton in Washington, D.C. "Most people will probably get one of them, some will get one or two and then a small group will be affected by a number of them ... it's all about your individual circumstances."

Of course, businesses benefit, too. For instance, both the House and Senate plans include a "net operating loss carry-back" tax break that allows companies to use existing losses to offset taxes paid on profits in the previous five years, up from the current two years now.

"This is a tremendous amount of cash that [business taxpayers] can get simply by filing returns or adjusting withholding," said Clint Stretch, managing principal of tax policy at Deloitte Tax. (The House version lets firms use up to 90% of their losses while the Senate version allows for 100% of losses.)

Keep in mind that most of the tax breaks are short-term, lasting only a year or two. And stay tuned for any changes in the final law -- Congress aims to send a bill to the president by Monday.

Here are some of the key tax provisions for individual taxpayers:

Both the House and Senate bills include a new refundable tax credit of up to $500 for working individuals and $1,000 for working families for 2009 and 2010.

Whether you're eligible may well depend on how lawmakers meld the two bills: In the House version this break starts to phase out when adjusted gross income reaches $75,000 for single and head-of-household filers and $150,000 for married-filing-jointly filers.

But fewer people qualify under the Senate's bill: The phase-out starts at $70,000 for single filers and $140,000 for joint filers.

The alternative minimum tax needs fixing by Congress. Without a temporary "patch," millions of taxpayers would fall into AMT eligibility, costing them many thousands in additional taxes.

But every year, Congress enacts a law raising the exemption amounts for one year, ensuring that fewer people have to pay the AMT. The Senate stimulus plan shells out the $70 billion (i.e., in lost revenue) necessary to protect a good chunk of taxpayers again this year. That's not a part of the House plan, but either way it's all-but-certain Congress will pass another AMT patch later this year.

"I think it's there to get Republican votes" for the stimulus bill, said Mark Luscombe, a principal analyst with CCH Inc., a Riverwoods, Ill., tax publisher. "They wanted to increase the tax breaks and that's one everyone could say 'we're going to do it anyway, so we'll do it now.'"

If you are among the millions who would face "alt-min" without the fix, this is a big deal. But you were going to get this relief anyway, with or without a stimulus.

This one-time payment of $300 for retirees, disabled individuals, Social Security beneficiaries, SSI recipients and veterans receiving veterans' disability compensation and pension benefits is in the Senate bill but not the House bill, so it's unclear whether it will make it into final law.

Don't confuse this with the "recovery rebate credit" which taxpayers, on their 2008 return, can claim if they may now qualify for last year's economic stimulus payment.

Another change proposed in both bills for the next two years makes the Hope credit worth up to $2,500 and good for four years of college costs (instead of the current limit of two).

The credit phases out when adjusted gross income hits $80,000 for single filers or $160,000 for joint filers. That means more people are eligible: Under current law, the Hope credit phase-out in 2009 starts at $50,000 for single filers and $100,000 for married filers, said Bob Scharin, senior tax analyst from the tax and accounting business of Thomson Reuters. "This is significantly higher," he said.

His colleague agreed. "This will help a lot of people with kids in college, and this might be the kind of provision that they eventually make permanent," said Jim Seidel, director of federal tax content for the tax and accounting business of Thomson Reuters. "But, again, this is something that depends on your circumstances. If your kids have already been to college or aren't going for a few more years, this isn't going to help you now."

The versions vary greatly between the House and Senate, but if you are in the market for a new house (or bought one since the start of this year), there is real help to be had here. The House bill eliminates the repayment requirement for the up-to-$7,500 refundable first-time home-buyer credit, unless the home is flipped within 36 months of purchase.

By comparison, the Senate would provide a one-time 10% tax credit up to $15,000 on the purchase of a principal residence. That credit can be used over two tax years (making it worth more to low-income taxpayers who could never use a $15,000 credit in a single year) and is not recaptured provided that the home is owned for at least 24 months. The Senate's credit is for a home purchased within one year from the date the stimulus bill becomes law. Stay tuned for the final details on this law.

The Senate bill creates a deduction for interest paid on car loans and state sales taxes paid on new car and light truck purchases. The interest can be on debt of up to $49,500 for cars purchased after Nov. 12, 2008 and before the start of 2010.

If you are in the market for a new car, this might be a great deal, but with manufacturers like GM pushing 0% financing deals, you actually may have to take a lesser financial package to get the tax savings.

This one sounds great, but it's nothing to shout about when you do the math. Both the House and Senate temporarily increase the earned income tax credit to 45% of the family's first $12,570 of earned income for families with three or more children. They also make this credit available to more people by, generally, raising threshold levels.

"The actual dollars in the pocket here will not be huge," Luscombe said. "You get 5% of an additional couple of thousand dollars, so it would be a few hundred bucks if it applies to you." Still, for a lower-income family, that's not bad news.

If you have dependent children, both bills increase the eligibility for the refundable child tax credit in 2009 and 2010, but the House is more generous than the Senate, as it eliminates the floor at which this credit starts, while the Senate just lowers it to $8,100 from $8,500 now.

Here's how it works: Right now, the tax credit starts to take effect when you have $8,500 in earnings or more; you get 15% of your earnings up to a limit of $2,000. The House bill allows the credit to start phasing in at $1 of income; the Senate bill at $8,100.

The House's version, which targets the provision to lower-income taxpayers, is a good way to stimulate the economy, said Len Burman, director of the Tax Policy Center, a joint venture of the Urban Institute and Brookings Institution in Washington. "If you give $2,000 to someone earning $13,000, they pretty much have to spend it because they're living on the edge. If they're earning $100,000 they're more likely to bank the money," he said.

Andrea Coombes is an assistant personal finance editor for MarketWatch, based in San Francisco.
Chuck Jaffe is a senior MarketWatch columnist. His work appears in dozens of U.S. newspapers.