We have supplemented our income with plenty of add on packages, local partnerships (jet ski/boat rentals, breweries, restaurants, etc)

This allowed me to supplement my real estate cashflow. 

I will raise steady income with an engineering salary and supplement that income with REI until it’s at the point where it’s more like my salary is supplementing my REI income. 

We wanted a new primary residence, and wanted to find something we could have a rental on the same property to supplement our mortgage payment.

All of the BiggerPockets podcasts are great supplemental learning material.

I won't get into STR until I have a LTR portfolio large enough to supplement the inconsistencies of STR in my market, if at all.

Are you looking for cash flow to supplement your military retirement? 

- Purchased a 1960's vintage building, 18 units, in 2017 for $1.5M- In a major urban city in the northeast- Put $400K down and have paid down $100K in loan (so the balance is $1M)- Purchased it to supplement my 9 - 5 and use it as a resource of income to retire (15 20 years from now)- It's comprised of studios, 1 bedrooms and 2 bedrooms. 

Investing is a supplement and a hedge, but you earn more for all of your investments, but upgrading your salary or wages year over year.

I think it's something like "supplemental lines"  where those providers fall outside the normal providers somehow - which gives them price permissions to charge more for their product - but at least you get the insurance.