We ended up going the HELOC route on that property for a few reasons. 1) the interest at the time was only 5%, which although seemed high, didn't matter too much with our potential property showing a 18% ROI 2) we leveraged a second home loan with 10% down for that new property, so our HELOC withdrawal was relatively small compared to what would be needed for a traditional loan on a rental. 3) I dont think I will see the rates in the 2% again in my lifetime, so figured I should hold on to that "free money" instead of selling it. 

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?

.- Streamline Process: Bypass the bureaucratic hurdles of traditional lenders.By leveraging hard money loans, home equity lines of credit, partnerships, and private lenders, you can boost your ROI and take your real estate investing to the next level!

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.  

@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.