The 50% rule states that approximately 50% of EGI will typically be consumed by operating expenses.While the 50% rule provides a quick estimate, actual expenses can vary widely depending on the property type, location, age, condition, tenant mix, and market conditions.Here's an example: if a property generates $200,000 in EGI per year, the 50% rule suggests $100,000 would go towards operating expenses like taxes, insurance, utilities, and property management.

@Marlia Stone The advice to get the first unit running and rented to generate some money is spot on.

My idea was to establish myself with some paid-off, cash flowing properties to make leveraging them for more investments a lot easier.I'd like to flip some houses to generate some cash, but  even knowing what I know I'm struggling to see how to make money doing so. 

I rent to adults.You have already spent too much time and energy on these people. 

Of course, if you then generate additional taxable income, that is something you can work to mitigate with your CPA.You could choose to form a self-directed IRA and invest the money directly into real estate.  

That will generate a massive tax bill.

And do it with a smile and energy unknown to most. 

Finding it difficult to run numbers and get a solid feel if the condos I'm looking at will generate the interest needed through the year.

This is a good model but doesn't account for a return of the $500k your parents will contribute..For example if the property generates $10k per month with $6k in PITI & operating expenses the proposed return for your parents would be: $2k and $1k for each of the minority partners.

I have tried using some, from time to time, and there are times that they device won't even work because there is not enough energy in the Harbor Freight battery.