First is the absolute auction or auction without reservation.  In this type of auction the seller is legally required to sell the property at the
auction regardless of the final high bid price.  The main advantage of an absolute auction is that it generates maximum response from the marketplace.
 
With a sale that is guaranteed regardless of the price, buyer excitement of the property can be maximized.  The main disadvantage is the real estate is
sold irrespective of the owner’s price requirements, however the lure of low prices usually create higher prices.

Second is the minimum bid auction. Here, the owners must sell at or above a stated minimum bid. The advantage of this type of auction is that it creates
the safety net the sellers lack in the absolute auction. Unfortunately it may limit interest in the auction only to those buyers who are willing to
pay the minimum bid price making it difficult to generate the right excitement level for higher bids.

Third is the auction with reservation. In this type of auction the seller reserves the right to reject the final high bid price. The advantage to this
type auction is the seller isn’t obligated to accept a price that’s entirely unacceptable. But many prospective buyers don’t want to invest the time and
expense investigating a property when they have no guarantee they will get the property even if they are the high bidders.