Real estate : you could become good at advertising and marketing or simply asking people you know if they want to buy or sell: Any realtor will give you $1k to $5k depending on the price to get that buyer  or seller.

You left out information that maybe relevant such as taxes/insurance per year, maintenance cost anticipated per year... plus other expenses depending on rental such as management fee(if you aren't manager), advertising cost to acquire renters, etc....

Effort is still required to communicate with the Craigslist advertisers, but having software to lift the deals out of Craigslist would surely be worth $1,000. 

These are the first things I look at.Lastly if someone is advertising on BP, it’s not a bad or good thing - all it means when someone advertises on BP or pays BP to be promoted it just means they paid to be on the website.

Where are you advertising?

Our realtor spends $30,000 per month on advertising.  

The best ones are the ones who dont heavily advertise in my experience

Tyler advertised (for $$$) a workshop on capital raising.

When you are purchasing a multifamily property, the seller will be advertising the property performs at a certain cap rate.

So its no major mystery that these are not performing as advertised..