Kuda Shumba goes at one speed: fast. He prides himself on being able to get hold of almost anything, and he's open for business day or night.

That's what it takes to be one of Zimbabwe's black-market cowboys.

Shumba spends his days on a motorbike sniffing out almost- impossible-to-find items such as sugar, cooking oil, bread, margarine or cellphone SIM cards, risking years in a dank prison if caught. His markup: 500%-plus.

His cellphone is his lifeline. He gets calls from a couple of dozen contacts who tip him off when a scarce commodity -- which nowadays in Zimbabwe includes all basic needs -- is about to appear in a store. Then he swoops in.

Store supervisors and other staff members sell most of what they have to people such as Shumba, pocketing a cut.

"I get them from the back door. You can't get them straight," he said. "I feel happy because I can get things fast and resell them quickly. That's my advantage: I'm fast. You have to be fast."

In this country suffering from hyperinflation, where the black market value of 1 million Zimbabwean dollars is $5.50, the underground dealers are the bane of the government. But President Robert Mugabe's increasingly draconian efforts to control the lurching economy by imposing price controls were a gift to them, triggering severe shortages.

Agriculture in Zimbabwe, once southern Africa's breadbasket, with a thriving tobacco industry, has gone into decline since early 2000, when Mugabe allowed the seizure of white-owned farms, most of which ended up in the hands of ruling party cronies. Production plummeted, investors fled, and the country has been struggling with severe shortages since.

Price controls meant some businesses had to run at a loss, so even more goods disappeared from the shelves. Although the government recently has increased some prices, the state-run newspaper Herald reports that widespread shortages persist.

"I can make a lot of money because the government is saying people have to sell this at 50,000 [Zimbabwean dollars], so businessmen are no longer buying these things for resale," Shumba said. "I'll make a lot of money, 30 million-plus" a month.

On the black market exchange rate, that would be $166. Still, it's a handsome salary compared with the 2 million Zimbabwean dollars a month, or $11, he estimates he would be making in his old job as a clerk, a post he abandoned in disgust several years ago because of the low pay.

Tall, wearing neat jeans and a crisp black jacket, the 34-year-old carries a briefcase and looks like a businessman or shop owner. Sure, he's deeply religious and active in his church, but he has a motto in Zimbabwe's dog-eat-dog economy: Never give anything away for free.

When there is no meat in the shops, his wife and children eat meat. He has luxuries that none of his neighbors can afford: a laptop computer, satellite TV, a DVD player.

"You can only afford those things if you're a black market guy," he said. "They're not for people on salaries."

Most days, there's an air of anxiety in Zimbabwe's supermarkets. The freezer sections, once filled with meat and chicken, yawn emptily. The shelves where cornmeal, rice and bread used to be stacked are bare. But on other shelves, cakes, cookies, dog food and chocolate are piled up, at prices few people can afford.

When staples arrive, the anxiety turns to panic, and sometimes violence.

When people see a queue in Zimbabwe, they join it and ask questions later. According to local news reports, a queue to buy sugar snaking for 900 yards erupted into pandemonium in late July in the eastern town of Marondera. A security fence was toppled and a woman sustained a broken leg in the crush, before police with dogs were called. Days earlier, two people were seriously injured when a truck carrying cornmeal was mobbed in Bulawayo.

But business has never been so good for Shumba, who sells his goods secretly at night from his home, or delivers to special customers.

He might be one of Zimbabwe's economic winners, but he seems wired, constantly on edge. During a clandestine interview, he fingered his cellphone ceaselessly and shifted nervously in his seat at questions about the business.