What is the best way to secure funds in order to purchase "all cash"?

[J Shoe]

I have been looking to purchase my second fix & flip however I keep losing out to all cash offers.  I have also been looking at foreclosure and sheriff sales which want funds within 5 days.  Which is the best way to come up with cash. Home Equity Loans or HELOCS seem to have the lowest interest rates and are flexible so if I find a property I can move on it quickly.  Can someone give me some advice? Is there a better way to go?