– Project Payday is one of those sites that has testimonials of people who have earned thousands of dollars by getting paid to get trial offers. I’m not saying you’ll earn thousands, but it is legit and you can earn some extra cash. They assume that by paying you to do a free trial, you’ll either like the product and purchase it, or forget to cancel the trial and get charged for it. If you can keep track and cancel before you get charged (if you don’t want the product), then this is a great site for making some money.
You could try advertising more, for example, by putting up signs around the neighborhood, posting about it on social media, or having people you know spread the word. You could also try doing it in a different neighborhood that might have friendlier people, or do it in a time and place where there's likely to be a lot of people walking around the area (e.g., near a church before the end of a mass). https://buzzingofferbusinessinvesting.tumblr.com/