Multiply that by 6 and I could have 12-15 Homes/duplexes to rent.  

Let’s say a painter at $30 an hour multiplied by eight hours equals $240 dollars a day.

Multiply that by 0.9 to get max total loan.

Terms like "Return on investment", "Return of Investment", "Capitalization Rate", "Gross Multiplier", "50% rule" (although I like the 49% rule), etc.... need to be learned and understood.This site is invaluable for learning all this and more.So, to answer your question "won't the deals dry up", I answer, only if the United States becomes a totally Socialist Republic where no one can own any land.

That money will multiply and allow you to buy something big later on.

Can't take the best decade of RE (and stock) appreciation ever and simply plug in that rate and multiply by the number of extra investments you think you could've purchased but we're too busy dealing with tenants.Unless you were buying all cash.

Gross Rent Multiplier Method (GRM) - purchase price / gross annual rent (annual rent as if property is 100% occupied), this give you the GRM.

What I see alot on larger houses without equivalent comps is they take the price of a smaller house, calculate price per square foot and do some multiplying with the larger square footage.

Appraisers use what is called a GRM analysis to arrive at a value of income-producing building, which establishes a relationship between the Gross Revenue and Value by way of multiplying the gross revenue by an appropriate factor (GRM).

We tend to target a GRM (Gross Rent Multiplier) of 10 or less, which puts you just under the 1% rule.