I’ve found offer up very unreliable. Nextdoor won’t get you much traffic and the people who do use it, tend to be older. Craigslist is good because it covers a wide area, and a lot of people use it. FB is good because it has such a massive reach to people, local and distant. It really depends on what is being sold, but many things I want to sell I post on CL and FB for best coverage.