Affiliate Marketing Secrets

I’m curious to know if anyone has ever tried using your Local Craigslist to Sell deals you get from eBay or Amazon. The only problem I find is: knowing an item which has great demand but have a higher chance for a local to ring and pick-up that item, I think it highly depends on the ‘saturation’ or how many peeps covers your CL (Craigslist) area.
Not even that but doing the same in eBay or Amazon but I don’t like to bother coming and packaging for shipments. Niche items like a Laptop or an iPhone? What are the chances? Have you done such?

I mean, let’s say there are stock market investors. Is it a good idea for you guys to be constantly telling new people, won’t that saturate it? I don’t understand how people all over, on places like this can just tell others their methods. It doesn’t make sense, i’d keep it secret. Does the stock market experience saturation if too many investors join? I’m just wondering, I do not know.