Use vscript it will make your life a lot easier and would allow for expansion.
Here is a basic script that might work for you.
PHP Code:
// Global variable for coins.
::Coins <- 0;
// Vscripting is weird about sending function variables as an output so keeping it simple.
function AddCoin()
{
Coins++;
}
function SpendCoin()
{
if ( Coins <= 0 )
{
ClientPrint(null, DirectorScript.HUD_PRINTTALK, "\x03" + " You don't have enough coins. " );
return;
}
Coins--;
ClientPrint(null, DirectorScript.HUD_PRINTTALK, "\x03" + " You have " + Coins + " coins left. " );
}