Everything costs more than you expect.
To budget, use actual quotes, reviews of past expenses, consideration of whether the location is in a more or less expensive geographical area. Give it your best estimate, then continually revise budget as needed. Track expenses by line item.
First, estimate the number of attendees to expect. Use past history and good judgment. From that, book block of rooms for hotel. Consider the timing of CE classes. Consider the number of association members who live in close enough proximity that they will not likely book a hotel room. Then, base meal costs on the number of expected attendees. For Monday, include exhibitors. They will not be there on Tuesday, and we almost never have a Tuesday-only attendee.
Many questions arose about sponsorship funds. There are two considerations here--how it is allocated, and what events are said to be sponsored by a given company or organization. In terms of allocation, the funds all go into a single line item. Along with exhibitor funds and registration fees, these offset the expenses. Sponsor money is not allocated to specific committes' expenses, not moved to individual line items. Choices about which sponsor's name to attach to specific events is a separate matter, handled by the sponsorship committee.
Finance committee will: