When. Weekend mornings, good weather/season for outdoor gatherings. You could do it indoors, but you will likely increase participation with an outdoor event. In my Utah city, I chose the first Saturday in June. The next one will be the last Saturday in September. (If the response continues to be positive, I will continue to annually hold 2 free swaps on those weekends. Over time people will be able to anticipate.) Avoid conflict with other major events in the community—summer festival days, college game days, etc. You can’t avoid everything, but you don’t want big-game-day gridlock clogging up the flow of traffic during your event.
Where. I chose to reserve a pavilion at the city center park. (I made the reservation 2 ½ months before the scheduled free swap.) Though I had to pay out of my own pocket for the reservation, it was worth it to me to have the security of a roof in case of rain. The other benefit of reserving the pavilion was having 16 sturdy aluminum picnic tables to use to display items. If you don’t have available tables you will need to track down people willing to donate folding display tables for the duration of the event. NOTE: LABEL ANY ITEMS—TABLES, CHAIRS, ETC.—THAT ARE BEING USED FOR THE EVENT SO GUESTS KNOW TO NOT TAKE THEM. I chose a location that had steady traffic and a parking lot nearby, thus facilitating unloading and loading of goods.