The costs are not trivial, but they are less than you would pay for a nice used truck.One of the main reasons I am considering this route is the leads that are provided.

Although the study may increase the gain, the gain may be taxed at a much lower rate making it a beneficial investment.If a property is purchased with the intention to flip or own for a short period of time (less than 3 years), a cost segregation study may not be significant.Overall, as long as you intend to hold the investment property for greater than a year, the benefits of a cost segregation study should be considered.

It all cash flows like a gold mine until the roof needs to be replaced, the main line goes, or you get your first turnover bill and need to upgrade a kitchen. 

The other main way I did it was by just telling people that I invest and kind of just talking about it all the time.

They have a payments 3rd party website, but it's hard to find the link from their main website. 

Instead I want to take advantage of the opportunity I have of living rent free to invest my time and money in STR's to hopefully build that portfolio up and eventually make that my main source of income (I understand that will take time).

My main question is whether it makes more sense to go the seller financing route and pay off the principal in 8–10 years or stick with a standard 30-year loan.My thinking is that the tax deductions from a mortgage wouldn’t outweigh the potential equity I could gain over those 8–10 years.

Lenders stopped allowing rent by the room due to modifications done to the property resulting in functional obsolescence and significant cost to cure in the event there was a default and they needed to foreclose on the home and resell it, given that the main buyer pool for single-family homes are primary occupants. 

DSCR loans don't require all of those things - your FICO and the income from the property are the main determining factors.

Multi-family properties are a great way to start since you can house hack and offset costs.What’s the main goal for you?