Want more time off work to hang out at the beach? Need a little cash and have vacation days to spare?

Some companies allow their workers to buy and sell vacation time, a perk that gives workers more flexibility in managing their time off.

The novel approach might help employees buy some extra days off to take the trip of a lifetime or spend more time with a newborn. Co-workers could sell off unused days to get some extra money.

“When times are a little tight, this benefit really doesn’t cost a lot of extra money to employers to provide,” said Julie Stich, research director for the International Foundation of Employee Benefit Plans. “It’s offered by more forward-thinking or flexible-type employers.”

A soon-to-be released survey by the Society for Human Resource Management found that 9 percent of employers allowed workers to cash out unused vacation time. Five percent let employees purchase additional vacation days through a payroll deduction. An additional 7 percent allowed employees to donate vacation time to a general pool that can be used by other workers.

The approach is even more popular with employers that have “paid time off” or PTO plans that combine vacation time, sick leave and personal days into one comprehensive plan. About 52 percent of employers reported offering such plans. Of those, 19 percent offered a cash-out option and 15 percent offered a donation program. One percent give their workers unlimited time off.

The cost is usually one week’s salary, prorated over the course of the year. Employees often have to decide whether to participate during an annual fall enrollment process and it becomes part of their benefits for the upcoming year.

Nora Kouba, who manages company cars at construction materials giant USG Corp. in Chicago, said she used to buy an extra week off to care for her kids or take long summer vacations with the family. But these days, she tends to sell her excess vacation time.

“I loved having the extra week when I needed it, and now I like having the extra money,” Kouba said.

USG allows all 9,000 of its employees worldwide to buy or sell up to a week of vacation time each year. A little more than half of the company’s employees typically buy an extra week off, while just 5 percent sell a week, USG spokesman Robert Williams said.

“People really value their time and appreciate the benefit,” Williams said.

The company used to allow employees to buy up to two weeks of extra vacation a year. But Williams said it was too popular and was cut back to just one week to avoid scheduling problems in USG’s production facilities.

In most plans, the employees aren’t actually buying and selling time from each other, Stich said. Time sold back to the company goes into a pool and in certain cases, other employees can buy it. New employees who get limited vacation time during their first few years at a company are among those who appreciate the benefit most, she said.

Jeff Weiss, senior vice president of benefits at San Antonio-based USAA, said about 41 percent of the company’s 25,000 employees bought vacation time last year, while 11 percent sold it.

“We think time off is actually critical to productivity,” Weiss said. “When people take their time off to refresh and renew, we believe they service the members more effectively.”