Today, a share of Hovnanian, one of the nation's largest builders, can be had for 96 cents, less than it costs for a set of spare house keys. Banks, stung by plummeting mortgage values, followed. A share of Citigroup Inc. which cost $55.66 at the beginning of 2007, now costs $2.60. ATM fees can total $3 or more for using an out-of-network bank card. Since the start of 2007, shares in companies from every sector have been hit. -- General Motors shares have fallen from $30.30 to $2.22, less than the cost of a standard spark plug (about $3.79). -- New York Times Co. shares have fallen from $24.27 to $3.95, cheaper than the $4 cost of its Sunday edition. -- General Electric Co. shares fell from $30.30 to $9.08, cheaper than a GE two-slice bagel toaster at Wal-Mart, selling Tuesday on the clearance rack for $12. -- Office Depot is down from $38.27 to $1.26, less than a 12-pack of medium point Papermate BallPoint Stick Pens which runs $1.89. -- US Airways has fallen from $53.89 to $3.66, less than the current $4 cost of two in-flight coffees. The bargain-basement stock prices of America's best known companies present either the greatest opportunity of a lifetime -- or the biggest money pit this side of the Great Depression. Of course, many didn't survive then -- and many won't survive now. Someone who bought shares of Circuit City, which cost $5.75 before the one-time retailing bellwether announced it would close, would have been better off buying a four-pack of AA batteries. The company is now selling furniture and fixtures from its headquarters as it liquidates.