I think you answered your own question.
However, if you are still unsure try hosting a small party of 5-6 couples... supplying location, snacks, sodas, decorations, and maybe entertainment of sometype. Add up your expenses, along with time to collect supplies and the time and cost of inviting 5-6 people.
Another cple and ourselves hosted a small get together at the beach Cost: Rented a penthouse (300.00-2 nites), purchased snack and soda's (150.00), prizes (for games, $50.00), decorations (30.00)...Total=530.00 Ads up quick! and doesn't even include my time planning, collecting items or inviting people.