Guide Price: An indication of the seller's current minimum acceptable price at auction. The guide price or range of guide prices is given to assist consumers in deciding whether or not to pursue a purchase. It is usual, but not always the case that a provisional range is agreed between the seller and auctioneer at the start of marketing. As the reserve is not fixed at this stage it can be adjusted by the seller at any time up to the day of the auction in light of the interest shown during the time that the guide price has been issued. The guide price can be shown in the form of a minimum and maximum price range within which an acceptable sale price (reserve) would fall, or as a single price figure within 10% of which the minimum acceptable price (reserve) would fall. A guide price is different to a reserve price (see definition). Both the guide price and the reserve price can be subject to change up to and including the day of the auction.

Reserve Price: The seller's minimum acceptable price at auction and the figure below which the auctioneer cannot sell. The reserve price is not disclosed and remains confidential between the seller and the auctioneer. Both the reserve and the guide price can be subject to change up to and including the day of the auction.