Ok, well, here it is. A program that allows you to limit the number of credits the players have per boot.
[Download here]Included are 2 files:
coinlimit.exe - the main program which you will want to run at startup
coinlimit.ini - the ini file where you can specify how many credits are available per boot.
Update [5/23/05]:You can now configure the keys used for the coins! Just open up coinlimit.ini and edit the "Keys" section (for each coin, just enter the letter/number of the coin -- not the ASCII code or anything like that!).
Note: that if you do not enter a key for one of the coin "slots", it will default to the default MAME key (5,6,7,8).
Please note: Only works on Windows NT/2000/XP. Does not work on Windows 95/98 (Sorry -- I wish it did too

.)