So, you could not combine IRA money with personal money or money you have personally borrowed from your current 401k plan.I did want to step in and thank @Matt Devincenzo for his important addition to the thread.  

Lets say I purchase a property with one of the following or combination of the following methods: cash, revolving line of credit, private lender, credit cards or SDIRA. 

If you combine flood zone with hurricane insurance on a property it will kill cash-flow.

Re-invest in RE with the equity3) Take no money out and accumulate cash reserves to re-invest in building #24) A combination of 1 & 2 or 1 & 3. 

We offered to pay for garbage and the water bill up to $50 combined each month (which our tenants love that we do), so our total Cash Flow = $531/m.We are now waiting the 6 months to hold before refinancing and looking to try to repeat the process with the equity that we pull out.  

Such is the relationship between cash on cash return and IRR, so you have to find the combination that works best for you and fits with your strategy.

A combination of them all.

I wanted something modern and comfortable but I was on low budget and couldn't hire a designer.Somehow I came across a web application that helps to design a kitchen to an ordinary user.

Knowing how to underwrite a deal is a combination of knowledge and experience.

Private financing would be ideal and you could use a combination of the two to fund the entire deal.