Buying third property, cost effective source of downpayment?

[Cynthia McWilliams]

We're thinking about buying a new primary home and renting this one out because the income would be great. We already have a rental property that is cash flow positive. Both properties are also worth considerably more than when we bought them, and we have about $150k in additional untapped equity in our primary home. Problem is that we have no downpayment money on hand. Our debt outside of mortgage is $60k to a 4.25% HELOC. No credit card debt.

I'm not sure what our downpayment options would be aside from pulling money out of retirement funds, getting a salary advance (if that's even possible), or increasing our HELOC (which seems risky). I don't think it would be cost effective or possible to get a place without a downpayment?

Thoughts?