MELVILLE, N.Y. – At 75, retired doctor Sidney Austein of Merrick, N.Y., is typical of his age group in at least one respect: When he needed a new car, he bought American because he thought it was the right thing to do for the country. His ride is a Cadillac CTS, purchased recently from octogenarian car dealer Paul Conte in Freeport, N.Y.

“I heard they’re better now,” said Austein, who had a bad experience in the 1970s with an American-made Pontiac and had been buying Toyotas ever since.

Americans who are middle-age and older, like Austein, dominate the new car market, accounting for 73 percent of buyers and lessees, according to the California-based market research firm J.D. Power and Associates.

As baby boomers age, their “green power” has grown with their numbers, says Power’s auto research director, Jon Osborn. “The economy has knocked the younger folks out of the market, leaving more of the more financially secure, older consumers to buy and lease new vehicles,” he wrote in an email.

The stumbling economy has put everyone who has the wherewithal into the driver’s seat in the supply-demand balance that determines the actual sales prices of cars, experts say. And even if the buyers’ credit is less than pristine, experts and local car dealers say, financing is more available than it was at this time last year.

Austein said he has wanted a Cadillac since the first time he saw the pink Eldorado his father-in-law bought new in 1957. “I kept saying, ‘I’m going to drive a Cadillac someday,’” Austein recalled. His CTS is silver.

He also wanted to buy American.

“The economy is lousy, jobs down the drain. I said, ‘Let’s do something for America for a change — enough with the foreign cars.’“

Whether you’re in the market for a new 2011 or 2012 or a “pre-owned” ride that will be new to you, experts suggest taking precautions and doing your homework for the best deal.

Here are some of their tips to help make your purchase a happy one.

Determine the type of vehicle you want and how much you want to spend for it.

Get quotes from several dealers for the model you want — in person, via email or by fax.

“What helps you buy a car cheaper is going to a couple of dealers and getting prices,” said Robert Certilman, owner of Smithtown Acura.

But, he cautions, be sure the quotes are for exactly the same car — model and equipment. Some experts suggest obtaining dealer quotes via email or fax so you’ll have them in writing.

Ask friends and family to recommend a dealership. You could check for complaints with the Better Business Bureau, though that’s not foolproof.

Get out your magnifying glass and read the fine print of ads that seem to be too good to be true.

Sometimes there’s a catch, like a low mileage limit for a lease, or a requirement for excellent credit to get a low interest rate on a loan.

During your test drive, be sure you can comfortably operate all of the vehicle’s controls — including those newfangled ones that operate like a computer, with a mouse and screen. Some can be dangerously distracting.

Don’t sign anything without reading it. Try not to negotiate or sign anything when you’re tired or hungry, advises Philip Reed, senior consumer advice editor of the auto information website Edmunds.com.

“A lot of people have said to me, ‘I signed just to get it over with.’“

Be aware that the “invoice price” the dealer is willing to show you is not necessarily what the dealer actually paid for the vehicle.

The Federal Trade Commission notes on its website, FTC.gov, that it’s “the manufacturer’s initial charge to the dealer” and often gets reduced by rebates, allowances, discounts and incentive awards to dealers.

Reed says his website’s “true market values” try to take most of that into account, but he added, “There are a lot of moving pieces behind the scenes.”

Simple is better. Reed says there are fewer chances of getting flimflammed or confused in a straight cash-for-a-car deal — with no trade-in and no dealer-arranged financing. Negotiate a price for the car first, he says. Then, if you want any of those added services, talk about them separately.

Beware of last-minute add-ons. In an email, a spokeswoman for the New York State Attorney General’s office said, “The No. 1 complaint we hear is that people feel they are pushed into buying many extras that they don’t need or want. For example, service contracts, extended warranties, various theft devices.” And make sure any dealer-installed items don’t void your warranty.

Consider a lease if you like to change cars every three or four years and are always making car payments anyway. Be aware, however, that many financial institutions that got burned a few years ago, when used vehicle prices collapsed, are setting more realistic — i.e. lower — “residuals,” the anticipated value of the vehicle at lease end. The lower the residual, the higher your monthly payment, all other things being equal.

Learn your credit score, then shop for financing. The dealer, with a manufacturer’s assistance, might offer the best — and most convenient — loan, but you won’t know for sure until you check.

An unscrupulous dealer might talk you into a high interest rate by falsely claiming that your credit is bad, says Certilman. He notes also that signing a credit application at a dealership doesn’t obligate you to take the loan if you don’t like the terms offered.

Get an insurance quote on the car before you buy it; some models are surcharged for high theft rates or high costs for replacement parts.

WHAT OLDER DRIVERS ARE BUYING

In a survey last year of people who bought cars between May 2009 and April last year, buyers 65 and older:

• Bought more Buicks, Lincolns, Cadillacs and — when they were still available — Mercuries than younger folks. But most gravitated toward the same brands as everyone else: Toyota, Ford, Chevrolet, Honda, Nissan and Hyundai. Among younger buyers, Honda displaced Ford in second place.

• Were somewhat more likely to buy certain SUVs — such as the Honda CR-V and Chevrolet Equinox — than younger buyers, despite those vehicles’ perception as being designed for families with young children.

• Were somewhat more likely than younger people to buy Detroit brands but were much less likely than younger ones to buy European models.

• Were somewhat more likely than younger people to buy the most popular hybrid model — the Toyota Prius.

INTERNET RESOURCES

Free websites to help choose your next car and dealer:

• NADA Guides: An excellent shopping tool, with list prices, photos, specifications, side-by-side comparisons, reviews, a dealer inventory locator and used car values. www.nadaguides.com

• Free credit report: A service for consumers to request free annual credit reports, created by the consumer credit reporting companies — Equifax, Experian and TransUnion — in accordance with the Fair and Accurate Credit Transactions Act. www.annualcredit report.com

• Better Business Bureau: Check a dealer’s complaint record. www.bbb.org

• Federal Trade Commission: Questions to ask before buying an extended warranty or service agreement. 1.usa.gov/p1pZr9

• Kelley Blue Book: For dealer costs, retail base and options prices, vehicles specs and more. www.kbb.com

• National Highway Traffic Safety Administration: Check safety ratings of vehicles. The tests got tougher for 2011; many of the newest models score lower than their predecessors or other pre-2011 models. www.safercar.gov

• Insurance Institute for Highway Safety: Safety ratings from this organization often find fault with vehicles highly rated by the federal government. www.iihs.org/ratings

FEE-BASED WEBSITES

• Consumer Reports: www.consumerreports.org

• Vehicle history reports: Two of the well-known websites are Carfax and Auto Check; useful to help insure that a used car isn’t a salvaged wreck or stolen vehicle. www.carfax.com and www.autocheck.com.