A reserve price is the lowest price that the seller is willing to accept for the item.
A reserve price can only be set on public auctions - this includes both standard auctions and extended auctions.
If the listing ends without any bids that meet the reserve price, the seller is not required to sell the property.
As a buyer, you are not shown the reserve price.
When you bid on an auction listing with a reserve price, you will only find out if the reserve has been met at the auction end.
If a property does not get a bid over the reserve price, the seller will be able to start a new auction when they are ready to try again.