What is the best method to fund your seed money for an investment property

[Haemi Jung]

I have about $40K of savings that we can use to start us off but I would like to see if there are other options to get more seed money. 

As I'm researching the best way to fund investment properties, I'm seeing an ad to fund your investment property using your 401K. Or is a home equity line of credit still the popular method?