variable x \ comma needed?
: Q ( q -- ) ?dup 0> if x @ if ." , " then 1 x ! . then ;
: M ( n m -- >1 =1 ) /mod dup Q dup 1 > swap 1 = ;
: F ( flag a u -- ) rot if type else 2drop then ;
: pennies-exchange ( n -- ) dup 0= if ." ERROR - "
    ." Must enter a number greater than 0!" else 0 x !
    10000   M   s" hundred" F   s" hundreds"    F
    5000    M   s" fifty"   F   s" fifties"     F
    2000    M   s" twenty"  F   s" twenties"    F
    1000    M   s" ten"     F   s" tens"        F
    500     M   s" five"    F   s" fives"       F
    100     M   s" dollar"  F   s" dollars"     F
    25      M   s" quarter" F   s" quarters"    F
    10      M   s" dime"    F   s" dimes"       F
    5       M   s" nickel"  F   s" nickels"     F
    1       M   s" penny"   F   s" pennies"     F then drop ;
David Smith - david.a.c.v.smith@gmail.com