This can be something fairly minimal, so long is it produces legitimate income that you report on your taxes, such as with a schedule C.  

We have had other candidates who say they are self employed but our process requires tax returns - although we have had a couple who could produce the appropriate pages, most of them go on to admit they don't report it and thus are unable to verify the income.

It seems unlikely to me that paying retail for a rental property will produce great cash flow.

My interests are not only limited to real estate, anything that produces income will intrigue me.

Here is a blog where I wrote about a recent 42 unit we bought and did creative things to add value. https://www.biggerpockets.com/renewsblog/bought-multi-million-dollar-apartment-complex-age-26/Just a few ways to produce ancillary income:- Laundry Coin laundryDetergent/laundry essentials in a vending machine in the common area laundry rooms.Rent individual W/D to each unit-Parking Garage parkingCovered parkingprime spot parkingJust plain old charge for parking-Renovations Interior units upgradesCommon area renovationExterior upgrades for curb appeal-Vending machines In common areas such as exercise room, pool house, laundry or leasing office-Trash pick up service In high-end buildings they have a service where you can set trash outside your door and for a fee maintenance will go around each night and collect it so the resident doesn't have to carry it to the dumpster.

As a buy and hold investor myself, I find it hard to sell something that I know will produce income.  

Instead of maxing out a 401(k) and losing access to that money, he can look at alternative investments that produce passive income.

Also, what is the outcome that you are trying to produce?

I suspect there is a different mortgage or sales price involved to produce that profit.  

Technically more since you probably don't commute on weekends and they'll be producing more content during those 3 months.