The Cost of Legislation
The final issue to consider before actually writing your bill is how much your bill will cost. In 2012, the federal government spent over $3.8 trillion - that's $3,800,000,000,000! Needless to say, that's a lot of money. The government spends it on lots of things--on programs as large and popular as Social Security, and on activities as small and unknown as repairs to the National Zoo. Together, these programs are what make up the federal budget. While the budget is written by the president, it must be approved by Congress.
The federal budget is a plan for how the government spends money and for how the government pays for its activities. Each year Congress and the president must decide which programs will be funded and for how much. For example, how much should we spend for defense, national parks, the FBI, Medicare, and meat and fish inspection?
(from the Office of Management and Budget, A Citizen's Guide to the 2012 Financial Report of the United States Government.)