The proposal writer must consider many elements when pitching a proposal in written form. One area that enhances your proposal and gives the reader a clear idea of what you are going to do is the budget.
Budgets are scary for novice grantseekers.
Good sense seems to dictate that after you develop your program and activities, you determine what it will cost. However, I don't work that way. My rule of thumb is that your budget reflects what it will take to do your project, no more, no less. Most proposals will give you a budget form to fill out. Follow that form.