HexCheat:

 It seems that the saved game files are consistent in size and come
 in at 225,745 bytes. This saved game file was created right at the
 start of game  (game1.sav) and the money amount was 19,990.
 Converting that to a hexadecimal value yielded 4E 16 and searching
 the saved game file for the reverse amount, found 16 4E in two
 locations near the end of the saved game file.
 It seems that hacking money into the first location will work and
 it may not be necessary to hack the 2nd location altho it is usually
 well advised that you hack both locations just to be on the safe
 side.  So here is a summary of the basic steps involved in this
 example:

 1) Convert your decimal money value to a hexadecimal value:
    19,990 Dn (decimal) = 4E 16 (hexadecimal)

 2) Search your saved game file for the reverse amount: 16 4E which
    was found in the following two locations:

    Location 1: Offset 207,340, hex 329EC
    Location 2: Offset 221,132, hex 35FCC

 3) Hack in your higher money amount.  To be on the safe side we will
    only hack in 5,000,000 Dn which is 4C 4B 40 in hex but to get
    that amount we hack in the reverse amount which mirrors the
    search technique that found the money locations in the first
    place:

    So for each location below where I have indicated where the money
    resides in the saved game file, change:  16 4E 00  to  40 4B 4C

    When you start your game up again you should have $5,000,000 Dn.