Even with 5 decimal digits, a 64-bit int can represent 184 trillion, which in dollars is roughly 3 times the entire worlds gross domestic product for 2010. Should be good enough for the average Internet reseller for a few years.
But those nice Nigerian bankmanagers who always propose me such lucrative deals, will run into problems and may in the end miss a few dollars left or right in their vaults. ;)
A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James