i think you should make a cash coin better, because player can trade or deal and don't worry about NPC Script when have bug to pump a cash point
this is a simple item_db + item script
29000,cash_coin,Cash Coin,0,10,,1,,,,,0xFFFFFFFF,7,2,,,,,,{ set #CASHPOINTS, #CASHPOINTS + 1; dispbottom "You gained 1 Cash Point."; },{},{}