PORTLAND, Ore. (MainStreet) — When you're a teenager, your car can put you on the road to freedom. When you retire, it becomes an anchor.

A fixed retirement income can transform car payments, auto insurance and weekly gas fill-ups from costly necessities to huge drains on the finances. If your stores, medical services, entertainment and transit options aren't all withing walking distance, a change of scenery may be able to help cut costs a bit.

The average household paid $8,293, or 13% of its $63,985 pretax income, on transportation costs in 2011, according to the Bureau of Labor Statistics. That includes purchase costs and car payments of $2,669; gas and oil charges of $2,655; and $2,454 for other expenses including insurance, maintenance, repairs and registration. In contrast, the average household spent only $516 on public transportation.

Adjusting that retirement income doesn't exactly do wonders for those car costs. Transportation accounts for 23% of gross incomes for those who made $15,000 to $19,999, but just 10% for those making over $70,000.

Neighborhood ranking site Walk Score has kept track of neighborhood density and convenience for the past couple of years and has helped real estate firms such as Zillow and Trulia pair retirees and other homebuyers with neighborhoods that make the most sense for their budget and lifestyle.

If downsizing the empty nest, ditching the car and diving into vibrant, tightly packed city life are on a retiree's agenda, However, many of Walk Score's top cities — New York, San Francisco, Boston, Washington and Chicago — are also among the nation's most expensive. With an eye toward cutting costs, we took a look at some of the less expensive options listed. They're still near some of the costlier locales, but aren't quite as spendy.

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5. Corvallis, Ore.
Walk score: 48
Transit Score: N/A

It's not as if Oregon towns such as Portland, Eugene and Hood river are bad options. All are incredibly walkable and have cheap or free public transportation for seniors.

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But the AARP put this town among its 10 great cities for retirement largely because of its free public transportation system (11 bus routes), wealth of bike lanes and inexpensive real estate. Tack on the fact that Oregon residents pay no sales tax and you're looking at an incredibly inexpensive option. Granted, you'll be surrounded by Oregon State University students and a town that fills up considerably a few Sundays a year for Beavers football games — the perils of living in a state three hours from the nearest National Football League team — but college towns such as this one, Ann Arbor, Mich., Madison, Wis., and others tend to be great picks for retirees thanks to the amenities and cheap living coveted by students and seniors alike.

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4. Chapel Hill, N.C.
Walk Score: 50.1
Transit Score: N/A

Remember what we just said about college towns?

By Walk Score's standards, this one admittedly isn't great for a stroll. We felt it required a mention if only for one particularly outstanding perk: The fare-free and extensive Chapel Hill Transit system. If you live in Chapel Hill or Carrboro, you'll have access to it and it gets you just about everywhere you'd need to be in this university town. Want to hit the restaurants, shops or Tar Heels games? They're yours, and for about a fraction of what you'd spend in cities just a bit up this list.

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3. Pittsburgh, Pa.
Walk Score: 60
Transit Score: 54

There's a knee-jerk reaction on the part of some would-be retirees to howl about taxes every time a Northeast location is suggested. Just stop it.

You're going to see Pennsylvania cities on this list a couple of times for one big reason: All the state's cities let senior citizens ride public transportation for free. In a town with a relatively low cost of living and great hospitals and attractions including the symphony, ballet, museums including the Andy Warhol Museum and reasonably priced tickets to Major League Baseball, that's not such a small amenity. Thank Pennsylvania's state lottery, which funds that transit perk and makes it extremely tempting for even jaded Northeasterners to bear the winters for a few more years.

Oh, and there's the small fact that the University of Pittsburgh Medical Center ranks among the nation's Top 10 hospitals for geriatric care. Not only is Pittsburgh still inexpensive and packed with great food, drink and culture, but it'll take care of you, too.

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2. Boulder, Colo.
Walk score: 56
Transit score: 49

The home of the University of Colorado, the Jack Kerouac School Of Disembodied Poetics, cruiser bike rallies and craft beer is not only affordable, but appealing.

Not shown in the rankings above is a Bike Score of 86 for a city that has hundreds of miles of bike trails to go with an extensive public transportation system with deep discounts for seniors.

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Now we're getting into the heavy hitters — towns where one in 10 people or more take their bike to work. To the University of Colorado students who make up 35% of the city's population, the biotech, aeronautic and defense company workers who bike through their commute and the two-wheeled travelers who help keep the city delightfully weird, the bike is the way to go in Boulder.

The city has more than 300 miles of trails, dozens of bike underpasses that speed riders past busy streets and a government-funded site, GoBoulderBike.net, that helps cyclists find the shortest route to their destination by bicycle, how many calories they'll burn along the way and how much they're saving in gas money by not driving. The overwhelming majority of the city's streets have bike lanes or easy bike access.

Boulder also sponsors a walk-and-bike month each June that includes free bike clinics, rides, tours, repair workshops and even happy hour drinks for riders. The city's efforts also get a lot of help by local bike groups, including the nonprofit Community Cycles, which hosts bike-in movies, bike collection drives, bike-trail opening events, bike workshops and clinics and "earn-a-bike" programs that allow Boulder residents to pay for a bike by working hours in the group's shop.

Boulder also knows it's a destination for more active retirees, so pool-having, trail-adjacent retirement communities with apartments as inexpensive as $725 a month abound.

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1. Philadelphia
Walk score: 77
Transit score: 67

The city's most walkable neighborhoods in Center City, the Old City and along the riverfront near Penn's Landing are pleasant enough, but the combination of easy transit access and building amenities such as markets, shops, bars and restaurant are bringing folks into Fishtown, Northern Liberties and South Philadelphia. Except for the extreme northeast, southwest and northwest corners of the city, about 95% of the city is easily accessible by means other than a car.

Transit ridership still has a way to go before it catches up to other cities along the Northeast Corridor, but retirees are joining young newcomers in places such as Manayunk and Kensington to take advantage of a city where the options are growing and the options for getting there are ample. Oh, and as is the case in Pittsburgh, the lottery keeps all public transit here free for seniors.

— By Jason Notte