Ever since Steve Crim graduated from Bladensburg High School three years ago, he has wanted his own apartment. This year, he hoped, would be the year he would finally stop living with his mother and sister. But last week Crim, a clerk for the federal government, resigned himself to postponing his apartment hunt for at least another year.

The news that dashed his hopes was President Carter's proposal that federal workers on the government's General Services, or "GS" scale, get a pay raise this year of 5.5 percent -- several percentage points lower than his 9.1 percent raise of last year, and less than half of the 12 percent inflation rate.

For all federal workers -- and there are nearly 300,000 of them in the Washington area -- the 5.5 percent raise translates into less spending power than the previous year. But the ones who say they are hurt the most are the 35,000 like Crim at the bottom of the GS scale who earn less than $12,000 a year.

They aren't policy makers in three-piece suits or the white-collar workers who earn an average of $23,000 a year. They are clerks, typists, secretaries and messengers at such places as the Pentagon, the Cenus Bureau and the FBI who are classified as GS4 or below. Contrary to the popular image of overpaid federal workers, many of them jus barely have enough money for food, shelter, clothing and a movie now and then.

What makes these federal employes especially bitter is President Carter's proposal that senior members of the executive branch and Congress be given a raise three times the size of theirs -- 16.8 compared to 5.5 percent. And at least some workers think they have a way of finding money for more raises -- by cutting waste in the federal government.

"The government blows money unnecessarily and then they take it out of our salary," said Pam Breed, a clerk at the Agriculture Department in Lanham. "You should see the furniture they throw away. They put our money into new chairs."

In some parts of the country, even lower-level GS salaries can buy a good quality of life. But Washington, according to the Bureau of Labor Statistics, is one of the most expensive cities in the country. A famiy of four here needs $22,206 a year in takehome pay just to have an "intermediate" standard of living.

By the bureau's standards, James and Grace Earp and their 15-year-old son have an "intermediate" standard of living. Both of them work for the federal government -- she as a GS3 clerk for the U.S. Census Bureau; he as a GS7 computer technician at Andrews Air Force Base. Between their two salaries, they take home about $18,000 a year.

Grace Earp spends her working days in a small room at the U.S. Census Bureau in Suitland opening mail. If the letter contains a check for a publication about demographics, she puts the check in a pile, which she later takes to the bureau's finance department. Then she sends along the request to the publications department, with a note about the amount paid. If the letter does not contain a check, she puts it in one of the numerous mail slots for the appropriate department.

Grace Earp figures that the 5.5 percent increase will erode their purchasing power, but not devastate them financially -- at least not this year. p

"But what worries me," she says, "is what would happen if we keep getting these low increases for several years."

The way Earp sees it, she or her husband would have to get a second job if the government continues to skimp on her cost-of-living raises. "Some people can cut out luxuries," she says. "We don't have any to cut out."

They spend about one-fourth of their take home pay on their home mortgage. They spend the rest of their income on food and clothes for themselves and their 15-year-old son, and on heating bills, car payments, car repairs and gasoline, which alone amounts to about $200 a month for their two cars. Once, they had a savings account, but they depleted that during the last few years, mostly as a result of inflation.

She has begun purchasing goods of lower quality than she would purchase in the past.

In addition, she and her husband have cut jout the "little luxuries" they used to enjoy, such as driving to West Virginia or northern Maryland for a weekend, or going out to dinner once a week. They haven't gone on a vacation in two years.

Under federal law, yearly changes in federal workers salaries are supposed to be the same as changes in salaries for private sector jobs, but the president can choose an alternate pay system and he has done so for at least the past two years.

Last year, salaries in the private sector -- except for some segments of white collar workers including all state and local government employes -- rose by 13.4 percent, but federal workers received only a 9.1 percent increase. This year, salaries in the private sector are expected to rise by more than 10 percent, according to officials of the American Federation of Government Employes, because of cost-of-living increases, yet Carter has proposed that federal workers get a pay increase of only 5.5 percent.

The advantages federal employes have are job security and benefits and pension plans that in many cases are better than those in private industry.

The 5.5 percent pay increase has made Earp feel, more strongly now than in the past, that the fat should be trimmed from such government programs as welfare and food stamps.

About 10 miles away, in a two-story converted warehouse on Aerospace Road in Lanham, Steve Crim, 21, selects different styles of type for books published by the U.S. Department of Agriculture. The books are about the soil quality of land throughout the Northeast.

Crim, who is single, is a GS3 who earns nearly $10,000 a year.

"That sounds like a lot of money," says Crim. "But it really doesn't go very far."

Some would say that Crim lives quite well. He recently spent $400 for a year's membership at a local health club, and he frequently goes out to dinner and movies with friends.

His secret?

"I live with my mother," says Crim. "I don't pay rent, and I don't have to buy food. It's easier financially to live at home."