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).
Still, many people need more than that to retire, let alone feel flush in retirement — so over time, that $500 monthly investment needs to increase. The best ways to do that are by investing any windfalls you receive or — better yet, and — increasing how much you save by 1% or 2% each year. A windfall might be any influx of cash you receive infrequently, such as a tax refund or employer bonus.
I came a low income single mother home. I earned two bachelors degrees, but had no car and no job to afford one. That killed my chances of working in either desired field after college. I worked part time for twelve years locally at a company, then was downsized. Mom died and I had to get an apartment. Still not enough money to risk getting a car when it could take from a month’s rent or more… that much closer to being out on the street with my belongings gone. I am really hopeful I can find something legitimate.