Mechanics of purchasing at a foreclosure auction with a cashier's check

I know you need to have the full purchase price for a FC auction but how does that work? Do we get one cashier’s check in the amount of our max bid? In that event, what happens if the opening bid is less than our max bid? We obviously woulnd’t want to pay more and how would we get change from our check? Or would we get several cashier’s checks in assorted amounts to total the max bid (e.g. a check for 100K, several checks for 10K each, and several checks in smaller amounts) that we then use to essentially give the auctioneer the exact amount…

Hi Kitma,
You can certainly get multiple checks for various amounts. The trustee will refund any overage to you (although it will take a few days and will typically come with your trustees deed, you will want to stay on top of the trustee and keep in contact with them until you get the overage returned). The auctioneer will write you a receipt at the time of the sale.
Many auction investors take one amount for the opening bid and then additional checks in smaller amounts.