Tiered pricing, table and zone seating, and door scanning fast enough for four hundred people arriving in the same twenty minutes.
New Year's Eve sells in three bursts - the November early bird, the mid-December decision, and the last forty-eight hours. Set the tiers once and let each one open and close itself while you work on the party.
No contract, no monthly fee, no sales call. You pay $0.50 when a ticket sells - and nothing if none do.