There isn't one normal rookie budget
Registration, extra events, parts, tools, travel, meals, shirts, outreach, and student support vary by program and location. Check current fees, quotes, and school procedures instead of borrowing one total from another team.
Put a date beside the assumptions that can change. A bus estimate from last year or a parts price from kickoff week may not belong in the final parent or sponsor packet.
Inventory the room before placing orders
Check the Kit of Parts, shop tools, usable stock, storage, cleaning supplies, and required protective equipment. Mark what is owned, what needs replacement, and what somebody still needs to verify.
Buy the tools and supplies you know you'll use first. When practical, wait for the design to settle before ordering parts that fit only one idea.
Separate confirmed money from hoped-for money
Keep registration, robot, tools, travel, meals, outreach, and reserve on separate lines. Do the same for confirmed school support, dues, fundraising, grants, and sponsor income.
A grant application or sponsor ask is not income yet. Showing confirmed and unconfirmed money separately gives the team an honest funding gap.
Price the order, not only the part
Add shipping, tax, package quantity, spares, and lead time to the bill of materials. Record the quote date and needed-by date when timing matters.
Put any team reserve on its own line. If the amount is zero, make that clear before the team shares the budget.