If they are able to rinse and repeat this type of strategy to leverage equity in a property to secure another, is it because they don't have a traditional mortgage loan on the properties they purchase?

Everyone knows the 3% or 4% balance transfer fee, but compare the fee to the interest you will pay over the same period with a traditional loan.If you have $10k in debt at an 8% interest rate with a traditional loan versus $10k of credit card debt with a 4% fee and keep both for a year (making minimal payments), you will pay less interest with the credit card.

Sounds like hard money/private money/fix and flip loan will be your best options here, not a traditional bank loan.

I already invested in 2 properties the traditional way (conventional loans) but am realizing that money is always going to be an issue.

This would avoid dealing with traditional lenders altogether.Partnership: Consider bringing in a partner who can provide the $140K in exchange for a share of the rental income or future appreciation.Cash-Out Refinance: If you have another property, you might be able to do a cash-out refinance to pull out the necessary funds.Best of luck!

Real estate is advertised as this great investment strategy but traditionally it takes a lot of cash to start. 

A small benefit could be the quads being purchased with traditional residential lending where as the 16 unit would require commercial lending.  

We used traditional residential financing and are prohibited by the terms of our mortgage from moving the properties into an LLC.

@James E.Hi James,I'm not a wholesaler... just an investor who has dealt with wholesale deals.My broad perspective is that wholesaling is a marketing job - where the wholesaler (on the surface) is trying to help a seller, but ultimately is trying to do that in a way that ends up costing the seller more money than it should have, had the seller taken more traditional means to achieve that sale.  

I have mostly seen investors use DSCR loans once they have tapped out all of the traditional methods.