Using TO_CHAR function with Numbers

TO_CHAR(number, 'format_model')

Format model elements:
9: Represents a number
0: Forces a zero to be displayed
$: Places dollar sign
. : Prints a decimal point
, : Prints a comma as thousands indicator

SQL> select to_char(6000, '$99,999.00') from dual;
TO_CHAR(600
-----------
$6,000.00