It usually costs about $70 to replace an exhaust fan, but federal watchdogs said a General Services Administration employee sentenced this week to more than two years in prison once paid a contractor $2,150 for the job.

In return, the contractor slipped Eric Minor an envelope stuffed with $1,000 in cash.

And when federal agents raided Minor’s home in December, they discovered more than $70,000 in cash — mostly $20 bills — stuffed in a box, watchdogs said.

Minor, 45, who had previously pleaded guilty to one count of bribery, was the last of 11 GSA employees or contractors to be sentenced for their roles in separate bribery schemes, prosecutors said. His sentencing capped a seven-year probe by the GSA’s inspector general’s office into the abuse of government-issued credit cards by GSA employees and contractors.

Over three years, prosecutors said that Minor collected about $118,000 in kickback payments on work he awarded companies when he was a GSA customer service manager. The job required Minor to hire companies to make small repairs and alterations at space owned or leased by the GSA, which owns or operates most federal facilities in the Washington region. He paid for the work — up to $2,500 per job — with a government-issued credit card, prosecutors said.

GSA Inspector General Brian D. Miller said his office began investigating claims of government credit card abuse in 2004 and found that several federal officials were using their cards to overcharge for work completed by contractors.

In February 2008, James Fisher, a GSA planner and estimator overseeing the agency’s operations at the White House, pleaded guilty to accepting bribes. He was sentenced to 18 months in prison and was ordered to pay $40,000 in restitution.

Later that year, Oscar Flores, a contractor at the U.S. Tax Court, pleaded guilty to bribing a court facilities manager, a GSA building manager and a GSA engineer. Flores was sentenced in April 2010 to six months of home confinement, three years of probation and 300 hours of community service and was ordered to pay a $40,000 fine.

Each subsequent arrest led investigators to other bribery cases involving engineers and building managers working for the GSA and the Treasury Department, and, ultimately, to Minor, Miller said.

“I think as a result, we’ve helped clean up the management of federal facilities in D.C.,” Miller said in an interview Tuesday. “It may just be several thousands of dollars, but it’s significant when you add up all of these individuals together.”

The GSA contractors who gave bribes and kickbacks to Minor remain at large, he said.

Agency policy required Minor’s supervisors to sign off on his credit card purchases, but they didn’t suspect irregularities because paying for contractor repair jobs was part of his duties, Miller said. In recent years, the agency has bolstered its charge card rules, but most of Minor’s offenses preceded the new policy.

Reams of watchdog reports have detailed the abuse, misuse and lax oversight of government-issued charge cards meant to pay for travel expenses and other purchases. In response, lawmakers are poised to pass legislation that would require federal employees using such cards to undergo regular credit checks, stricter limitations on purchases and regular reviews to see whether they still need the card.

Besides sending Minor to prison, U.S. District Judge Ricardo M. Urbinaalso ordered the Upper Marlboro man to pay $118,000 in restitution to the government. Minor was allowed to apply the $70,000 seized at his house toward that amount; on Monday, he wrote a check for $46,000 to make up the difference.

Minor cried in court Monday as he told Urbina that he was sorry for his conduct and that he was “a compassionate person” who deserved leniency. But the judge said Minor deserved prison time, noting that the GSA employee — who resigned Tuesday — took kickbacks on more than 300 small contracts he had awarded.

“Why did you keep on taking this money over and over and over again?” Urbina asked Minor.

“Stupidity, your honor,” Minor replied.

Federal prosecutors had asked Urbina to send Minor to prison for at least 37 months. But Urbina said he thought that Minor had lived an otherwise unblemished life and that 21 / 2 years was appropriate. He added that he thought Minor “was a good man driven by greed.”