Some people are using it for fun. Others are just hoping it will get them through tough times.

Still others need it to pay off debts, and a few people might just sock it away for a rainy day—possibly for future recreational use, or for a later obligation.

Like a drug to soothe the country’s financial ills, the economic stimulus checks are making their way into American checking accounts, where they likely won’t sit for very long.

Starting last week, more than 130 million households started getting between $300 and $600 per tax-filing person, $1,200 for married couples and $300 per child under 17. The total windfall amounts to almost $150 billion, and it could provide a $42.9 billion shot in the economy’s arm, according to one group who certainly hopes that number holds true: The National Retail Federation.

The first payments arrived last Friday for tax filers who opted for direct deposit. The IRS estimates the last rebates will be mailed by mid-July.

Retailers, car dealers and even environmentalists are all clamoring for the money, trying to convince grocery shoppers, car buyers and tree huggers that Uncle Sam wants them to spend their rebates.

Medved Autoplex in Denver is offering to triple customers’ rebate checks to put toward buying a car: “Medved is doing its part,” a commercial says, exhorting people to help stimulate the economy.

The dealer will triple customers’ personal federal economic stimulus check. That would be $1,800—not a bad down-payment. Of course, with gas prices around $3.50 a gallon, maybe a new car isn’t the wisest purchase, unless that check is tripled for a down payment on a Prius.

Grocery stores, including Kroger Co., which owns King Soopers, are offering extra money for shoppers who redeem their checks for gift cards—nice timing considering high food prices.

Some chain retailers like Home Depot are urging shoppers to spend their checks on energy-efficient products like light bulbs and Home Depot’s own Eco Options brand, according to AdAge, a marketing research firm.

And non-profits are encouraging well-intentioned taxpayers to give some of their extra money to charity.

According to a CNN poll, just 3 percent of respondents plan to stimulate charities.

At least one local nonprofit organization is hoping for a higher number—and a higher purpose for the extra green.

Trees, Water & People, an environmental group based in Fort Collins, is asking residents to consider helping their efforts to help the environment.

“We are hoping that people will take this money that they weren’t necessarily expecting at the beginning of the year and donate it to a good cause,” said Heather Herrell, development director for Trees, Water & People. “They will get double the impact of the money because it will be stimulating our local economy and then it also benefits people in the community.”

TWP joined forces with a Colorado group, Double-Duty.org, to stimulate eco-consciousness along with the economy. Other projects on Double Duty’s list include a project to insulate the Boulder Community School of Integrated Studies, and a Denver project, Groundwork Denver, that brings energy efficient light bulbs and other products to low-income neighborhoods.

Herrell said donations to TWP would be used to promote the organizations’ SunMobile project, a new traveling exhibit that educates schoolchildren about solar energy. It includes a solar-powered oven, which can bake cookies, and information about how to live more sustainably.

“This is the first time we’ve done something like this, so we’re not sure really what to expect,” she said of the stimulus effort.

Several Coloradans are already making other plans for the forthcoming checks.

Brigitte Davison, who was window-shopping in Old Town on a recent afternoon, said she will use the money for a landscaping project.

“We would do the yard anyway, but it’s nice to know we have that money coming to pay for it,” she said.

According to a survey for the retail federation, consumers plan to spend about 40 percent of their tax rebate checks. That spending equals about $43 billion, the federation estimated.

Another $30 billion will go to pay down debt; about $19.8 billion will be saved; and about $4.5 million each will go to investments or medical bills.

Of course, those numbers depend on your perspective.

CNN’s poll found that 41 percent of respondents plan to use their rebates to pay off bills, and 32 percent will put the money in savings. Just 21 percent of those polled intend to spend the money, a far cry from the retail federation’s optimistic number.

For some, the windfall will help stimulate savings accounts.

Jared Fowles, a graduate student at Colorado State University, said he planned to stash his stimulus check.

“I’m broke—I need to get a little more in savings,” he said.

Some students don’t even earn enough to qualify for a check—you have to have earned $3,000 last year. For those that do qualify, debts are high on the list of things to be stimulated.

“I guess mine’s going to rent,” said Dave Kapp, a CSU student.

Uncle Sam would probably understand.

The IRS warns taxpayers that identity thieves are already pushing scams involving the stimulus payments. At least one telephone scam is making the rounds using the proposed rebates as bait.

The goal of the scams is to trick people into revealing personal and financial information, such as Social Security, bank account or credit card numbers, which the scammers can use to commit identity theft, according to the IRS.

In one scam, consumers receive a phone call from someone identifying himself as an IRS employee. The caller tells the victim that he needs the target’s bank account information for the direct deposit of the rebate. If the target refuses, he is told that he cannot receive the rebate. The IRS does not force taxpayers to use direct deposit. Those who opt for direct deposit do so on their tax returns, with bank routing and account information, when they file; the IRS does not gather the information by telephone.

For more about other scams involving tax rebates or stimulus checks, visit irs.gov.