You are asking for a foundation's money as an investment in your project. The program officer needs to know how the money will be spent. Along with a strong narrative, you need to include a budget.
A carefully prepared budget should justify all of your expenses and be consistent with the activities listed within the proposal. There should be no surprise items entered on the budget that aren't mentioned in your plan of action. Some common budget areas include rental of building(s), equipment and resources, transportation, publicity, insurance, and food/refreshments. Personnel costs are also included and subtitled.
Remember to include only the costs that relate to this particular program and not ongoing administration costs that are not part of this grant proposal (unless you are applying for a general operating grant). In fact, you might even explain what will become of equipment after the project terminates. Will it be donated or put to good use for future projects?
Often, pro bono and in-kind services will be accepted as a source of a funding match. If your proposal states you'll match a grant with money or donations from other sources, you may be able to use volunteered services as part of your other donations. The value of volunteered services may need to be substantiated in the proposal by using average wages or a figure agreed upon in writing.
Indicate where the project will take place. Are the project personnel working out of an office? Are they using typical office equipment, such as copiers and telephones? If so, do the budget guidelines of the funder allow for space and usage of equipment to be considered as eligible project costs? Will meeting rooms, auditoriums, and audiovisual equipment need to be rented to complete the tasks of the project? These are legitimate project costs. Include them in your budget.
Make sure you list the various sources of income, including sponsors, donors, sales, grants, and so on. Foundations will want to know where other funding will come from. The foundation providing the grant will not usually be your primary source of funding but one of several. Many grant applications require that the applicant show matching funds and additional resources. Be sure to check the grant maker's guidelines so you know which expenses are eligible and which are not.