They would be OK with smaller margins, or maybe breaking even, as long as they got the quantity of deals to keep a pipeline of business going. 

Conversely, you have to vet and deal with a stranger living very close to you, whereas if the ex moves in, that's a known quantity.  

Also keep in mind you want quality, not quantity of leads.

@Sevy Bialke there are 3 things needed for a successful investment, 1) a deal, 2) the financing to purchase the deal, and 3) operations which could be managing a rehab project or managing a rental.I am not sure where you are at on 2 or 3 but if you can use your skills to find deals by pulling information and analyzing large quantities of data that could be your sales pitch to a partner.

People who say houses cannot be scaled or that there is no economy of scale in owning large quantity of houses are just incorrect.

@Jason The quantity of your mailing list should depend on your budget.

I first discovered the idea of passive income, financial independence, yada yada yada, a while ago, and have just been overwhelmed by the vast quantity of free information on the internet and in the books at my local library.

Some people love living in apartment complexes because of the amenities, it's frequent for SFRs nearby (if both are in good locations) to function in harmony because a steady stream of people will be looking to . . . get a yard for their (oversized, non-apartment-friendly) dog, get rid of the noisy upstairs neighbor, get a little more privacy, "move up" a bit, etc.  

One of the reasons we picked this company was because they said they would do periodic drive-bys to make sure all was well with the house.Yesterday, the neighbor texted us again and said the county sheriff, the fire department, and the local news stations had been at our house because the tenants were being arrested for possession of a large quantity of illegal fireworks.

We still invest in residential multifamily built 2000 or newer in markets with larger quantities of these available to consolidate management companies.