Purpose
The purpose for including a budget and a budget justification with your grant, of course, is to document the level of funding needed to support your project.  It may also document cash and in-kind match which your organization or another partner organization will contribute to the project.

Content
Typical sections are:

Personnel (might include director's salary; a portion of the salary of regular employees; student workers; stipends for employees)

Fringe Benefits (calculate fringe at the current published rate for the institution)

Travel (might include in-state calculated at the current allowable amount per mile; out-of-state; or out-of-country)  Worksheets are available in the Grants Office to help calculate travel costs.

Equipment (allowable equipment that is justified by the requirements of the grant--obtain bids)

Supplies (office supplies; printing; special purpose supplies; cost of mailings; multimedia materials related to the project)

Contractual (trainers; facilitators; external evaluators; other specialized services)

Construction and Other are two other possible categories.  Construction might include new construction or renovations.  Other should include any specialized need of the project not covered in another category.

Tip
Be realistic and accurate with your funding request.  Reviewers can recognize when a budget is padded.  They also recognize when an organization tries to make itself appear more competitive by estimating the budget low.  The best approach is to calculate accurately the resources required to accomplish your project, then request that amount.

Link for more information
Budget Justification Information
Foundation Center Budgeting Basics Course
Quick Tips

Next: Support/Commitment Letters