Ok yes there is the free option which requires diving in to cereal boxes. ;D
While under a dollar might have been a stretch, its damn cheap.
At Futurlec for quantities of one, a 32khz crystal is 75c and the DS1307 is $3.50.
Buying a couple slashes the price and the SMD chip is 60 cents less.
Futurlec also has a $6.90 board with the DS1307, a crystal, pull up resistors, decoupling capacitor and backup battery.
A pretty good deal. I've got one. 