Ready to have your mind blown? The rule is that if someone lands on a property and chooses not to buy it, that property goes to auction giving any player the chance to bid on it. The banker is the auctioneer. Game. Changer.
In the official Monopoly rules state:
BUYING PROPERTY… Whenever you land on an unowned property you may buy that property from the Bank at its printed price. You receive the Title Deed card showing ownership; place it face up in front of you.
If you do not wish to buy the property, the Banker sells it at auction to the highest bidder. The buyer pays the Bank the amount of the bid in cash and receives the Title Deed card for that property. Any player, including the one who declined the option to buy it at the printed price, may bid. Bidding may start at any price.
This means that you could potentially buy property for A LOT less than its selling price. Or, the person who landed on it could bid and get it for less than if they bought it when they first landed on it. Bankers, get your auctioneer voice ready.
Before you go and quickly round up your friends for a (new and improved) night of Monopoly, make sure you read up on these other little known facts about board games.