As he prepared to speak to his governing Conservative Party's spring conference in Cardiff, Cameron said the March 23 package would help Britain to hustle and earn its way in the world again.
The message comes amid criticism that the governing Conservative-Liberal Democrat coalition's plans for eliminating Britain's record deficit have focused too heavily on cutting public spending without a plan to kick-start the economy.
"In just over two weeks, our government is going to unveil the most pro-enterprise, pro-business budget for a generation," Cameron wrote in the News of the World newspaper.
"It's going to be a budget for the doers and the grafters, the builders and the businesswomen -- all those entrepreneurs who create jobs and money for the rest of us.
"We're cutting the business taxes and dealing with the nightmare of red tape and hold-ups that make life impossible for entrepreneurs."
He was to tell delegates: "We are taking on the enemies of enterprise."
These included government bureaucrats mired in rules and regulations, foot-dragging local authority officials and public sector procurement managers favouring big business over smaller firms.
He said a new Enterprise Allowance scheme would help people kick-start their business.
"If you've got an idea and want to start a business -- go for it. If you've got a business and want to grow -- tell us how we can help you," he wrote.
"Get a business plan together, and if it looks good, we will give you up to 2,000 pounds ($3,250, 2,330 euros) to get started."
Cameron added: "Think back over centuries of history and this country has always out-competed, out-hustled, out-innovated, out-enterprised our competitors. It's our generation's turn to show we can do the same."
His finance minister George Osborne said Saturday that his budget would set up "enterprise zones" across Britain to boost growth in run-down areas, saying they would be "centres for new businesses and new jobs where taxes will be even lower and more restrictions on growth removed."
He also hinted that a planned one-penny-above inflation rise in petrol tax might not go ahead, as the unrest in the Arab world pushes oil prices higher.