Image: Wallet © NULL, Corbis

You may be working yourself into the poorhouse.

Holding a full-time job is the way most people earn a paycheck and make ends meet. The catch is that the very act of working is costing you in ways that go far beyond taxes. For those struggling to get by on lower salaries, the impact of what it costs to go to work can put a significant squeeze on household budgets.

A flaw in the nation's unemployment safety net is that sometimes it can seem more lucrative (at least in the minds of the less-than-motivated) to stay at home collecting unemployment checks than to take a low-paying job.

For example, someone who is laid off from a $60,000-a-year position may find it difficult to justify turning down unemployment benefits that add up to as much as half that when a paid job also offers only half the previous income. Once that $30,000 starts being nibbled away by the many costs associated with holding a daily job, sitting on a couch, eating pizza rolls and watching TV might seem like a better deal.

Here are five expenses that can eat away at wages, followed by some advice on cutting the cost:

1. Tanks for nothing

There are commuting costs to contend with. If you have access to public transportation, prepare to plunk down $60 to $100 a month for a train or bus pass in most major cities. If you drive to the office, the costs shoot up from there.

Nationally, most low- to moderate-income workers -- more than 85% -- drive to work in private vehicles, according to research by the Center for Housing Policy, the nonprofit research affiliate of the National Housing Conference.

According to data compiled by the personal finance website, the average American worker spends more than $6,000 a year on transportation. That accounting includes not only fuel costs but other auto expenses as well (insurance, inspections, etc.). It is not just gas that will affect your personal bottom line. The wear and tear on your car that goes with a commute, not to mention the purchase price of the vehicle, also must be counted.

Depending on where you live, that budget item -- significantly affected by the length and frequency of work commutes -- can go much higher. A study last year by the Urban Land Institute found that, nationally, transportation costs are a household's second-largest expenditure (housing was No. 1). In research focused on the Boston region between 2006 and 2008, transportation costs consumed 19% of income for the typical household, amounting to $994 per month, or $11,927 annually. Forty-one percent of workers in that region had one-way commutes of a half-hour or longer, and one in 10 commuted at least an hour each way.

Add to the mix the pricey problem of parking your car if your job site doesn't offer it for free. In major cities, be prepared to have daytime parking set you back $300 to $400 a month -- or more.

2. Child-care dilemma

If you have kids, prepare yourself for what may be the biggest budget buster of all -- day care.

More than 11 million children under age 5 spend approximately 35 hours per week in the care of someone other than a parent, according to the National Association of Child Care Resource & Referral Agencies. On average, preschool-age children of working mothers spend 36 hours in child care or nonparental care.

More than half (51%) of families with children under 5 say the economy has affected their child-care arrangements in some way, with more than three-fifths (63%) worried at least some of the time about paying their bills, the group found in a recent survey (.pdf file).

"For many families, the cost of quality child care is simply too high," says Linda Smith, the association's executive director.

How high? According to the association, the cost of day care can fluctuate widely among cities, with major metropolitan areas commanding heftier prices. Full-time center care for an infant was found to range from $4,500 to nearly $19,000 per year last year. Center care for a 4-year-old child ran between $4,460 and $13,158 annually. Before- and after-school care for a school-aged child in a center can cost upward of $10,000.

The cost is forcing some working families to make difficult -- and questionable -- decisions.

"More parents are faced with having to choose unlicensed and unregulated child-care settings in order to save money," Smith says. "If parents are faced with deciding whether to pay more for child care or buy other household necessities like groceries, child care is usually the first area where parents make adjustments to reduce costs," Smith said. "In most instances, families are likely to spend more on child care than they do for health care and food combined."

Even those who think of their pets as children will pay the price for being at work. A dog walker will typically cost $15 to $30 per half-hour session.