Not long after the game began production at Parker Brothers, more than 20,000 games were being published each week. With that many games in circulation, the remaining supply is still big enough to keep prices down.
So you're not going to be able to finance your child's education by finding an old Monopoly game in your attic and selling it on eBay. In fact, a 1935 edition in decent condition sold in early 2003 for just $76. A 1937 edition with wooden pawns went for only $61.
The most expensive Monopoly set ever was a ruby- and sapphire-encrusted creation put together by San Francisco jeweler Sidney Mobell in 1988. With solid gold houses and hotels, and diamonds in the dice for pips, this game was worth $2 million.
The Franklin Mint has produced a deluxe collector's edition that I've seen available for $500 to $600 retail and $200 to $300 on eBay.