Unfortunately, in this day and age you need to keep your moneybox out of plain view. Keep some change in your pocket and the majority of your cash inside the house. Consider having a table for free items. Set up everything the night before to minimize your workload the morning of the sale. You might also want to hand out business cards advertising any other business venture you re involved in.
Garage sales are great places to make contacts and meet people.
Maybe even let your kids get a taste of the business world by letting them set up a refreshment stand with lemonade or cookies. Finally, don t be afraid to get hooked. I know of more than one person who provides a quite attractive second income with garage sales. Others do it merely as a hobby. Whatever your goal, when you see how much money can be made from stuff you were only going to throw out anyway, you will find yourself looking forward to your next garage sale.