Cash flow or capital building?

[Jack Stallion]

Greetings everybody!  This is my first post and am hoping for some advice.  I am wanting to begin the process of building a rental portfolio and need to make a decision.   Do I save, save, save to build enough capital to purchase a property outright OR look for 20% down and go get financing for the rest.  Building capital for an outright purchase will take a year.  The 20% down approach will take a few months.  Any thoughts?  Thanks!!!!