The good news is that once you get started, it becomes easier to find more opportunities. Many of these companies add you to their database so they can invite you to more studies when they become available. Of course, you always have the right to accept or deny any invitation. You are never required to participate in any study that you don’t want to.
Have a yard sale to sell things you no longer need. Choose a day or a couple of days to have your yard sale. Advertise it in your local paper and online, such as on social media and classified websites. Then, on the day of the sale, arrange the items on tables, blankets, shelves, or in other ways in front of your home. You can arrange the items into groups by price, or price them individually.