In my county (Fulton County, Georgia), when a home is auctioned off for tax reasons, payment must be made within an hour of the auction close. The payment must be made in cash or certified funds. How would I pay for a home purchased as a bank foreclosure? Same? It seems difficult to show up with hundreds of thousands of dollars in cash.
But you need one who will do "at the steps" funding. They can fund the same day of the auction.
Go to the local REIA to find a hard money lender.