STAFFORD, VA. -- Like any good businessman, Rod Kim knows his product and his customers. He knows the value of service, does his own books, deals directly with his suppliers and takes in a trade show now and then.

Unlike most of his competitors, Kim gets advice not from an accountant, but from his mother.

At the age of 16, Kim thinks business when most of his friends are thinking baseball. Eight months ago he started Weekend Hobbies, a remote-control car shop in Stafford County's Ferry Farms subdivision.

Though he had plenty of help from his mom, he has repaid his bank loan and has made a profit. Along the way, he's discovered what many adults already know: Starting a business can be a sobering, if not bewildering, undertaking.

"I first got into it two years ago when a friend got a remote-control car for his birthday," said Kim, a junior at Chancellor High School. "After I got a car, I got more experience and came up with the idea of opening a store."

The notion was not that unusual, because business runs in the family. His father, Sam, and an aunt are in the grocery store business in the Washington area.

His mother, Eileen Kim, owns Ferry Farm Cleaners. She also owns a small building around the corner from her shop that she was willing to let her son use rent-free. Kim said his mother secured a loan from a bank and he took it from there.

"I thought it was a great idea," said Eileen Kim. "He does the books. He has his own account and everybody thinks it's fantastic." She's lending a hand with paperwork and taxes.

Kim started reading trade magazines and hit up his friends for tips on what's hot and what's not. "I really didn't know how to get started, but Mom said to go to the distributors," he said.

His age, he said, was a problem at first. Suppliers were reluctant to deal with a child. Then Kim and his mother went to see them personally.

He now deals with three suppliers, but orders many of his cars and parts from Horizon Hobby Distributors in Ashland, Va. His initial order: $9,000.

Kim quickly discovered that opening the door doesn't necessarily mean you're in business.

"At first it was kind of slow," he said, "because we had trouble getting people to recognize we were here." Signs on the shop "are kind of limited by the county" and advertising is out of the question "because we're so small," he said.

Slowly, sales improved, mostly by word-of-mouth, he said. "Customers are mainly people my age. But I'd figure the group from age 10 to their thirties. Mainly it's kids who see somebody else with something real neat and they want to know where they can get it, and they send them to me."

Kim stocks hot models in the shop and confidently confides that he can order "just about anything."

Parts and kits are arranged in neat rows along the walls, there are stacks of hobby magazines and Kim does repairs on a workshop behind the counter. He also has business cards handy.

On the cash register is a sticker with the inscription: "The difference between men and boys is the price of their toys."

Men and boys can shell out plenty for a remote-control car kit. They run from about $60 to several hundred dollars. Forget about writing a check: it's cash only.

Brandon Kirtley of Fredericksburg, a friend and a regular customer, said of Kim, "He does a pretty good business doing it himself. The store is smaller than average, but it's pretty packed and he knows what he's doing."

The hours are long -- 10 a.m. to 7 p.m. weekdays and from noon to 5 p.m. weekends -- and don't leave Kim much time for traditional pastimes like hanging out with his friends.

When school starts he'll cut back his hours, on his mom's orders.

Kim doesn't expect to be selling the cars for a living.

"Mom wants me to get a good education. She doesn't want this to be the rest of my life," he said.