If you would like to use a credit card system with my bank script (found here: http://www.lomcn.co.uk/forum/showthread.php?p=650062#post650062)
Here is an example of how you would do it:
[@2times]
#SAY
For 100 Million gold you can have 2x EXP \
for 30 Minutes! \ \ \
<Buy with Card/@go2timescredit> - <Buy with Gold/@go2timesgold> - <Back/@goldshop>
[@go2timescredit]
#IF
CHECKNAMELIST ..\QuestDiary\Bank\Namelists\GotBank.txt
#ACT
Var Integer Human Bank 0
LOADVAR Human Bank ..\QuestDiary\Bank\Variables\Integral.txt
goto @paywithcard
#ELSEACT
SENDMSG 6 "You do not have a credit card!"
goto @2times
[@paywithcard]
#IF
CHECKVAR Human Bank + 99
#ACT
CALCVAR Human Bank - 100
SAVEVAR Human Bank ..\QuestDiary\Bank\Variables\Integral.txt
KILLMONEXPRATE 1800 200
SENDMSG 6 "You now have 200% for 30 Minutes"
SENDMSG 6 "You have <$HUMAN(Bank)> Million left in your account"
close
#ELSEACT
SENDMSG 6 "You do not have enough funds on your card!"
goto @2times
Here is an example of how you would do it:
[@2times]
#SAY
For 100 Million gold you can have 2x EXP \
for 30 Minutes! \ \ \
<Buy with Card/@go2timescredit> - <Buy with Gold/@go2timesgold> - <Back/@goldshop>
[@go2timescredit]
#IF
CHECKNAMELIST ..\QuestDiary\Bank\Namelists\GotBank.txt
#ACT
Var Integer Human Bank 0
LOADVAR Human Bank ..\QuestDiary\Bank\Variables\Integral.txt
goto @paywithcard
#ELSEACT
SENDMSG 6 "You do not have a credit card!"
goto @2times
[@paywithcard]
#IF
CHECKVAR Human Bank + 99
#ACT
CALCVAR Human Bank - 100
SAVEVAR Human Bank ..\QuestDiary\Bank\Variables\Integral.txt
KILLMONEXPRATE 1800 200
SENDMSG 6 "You now have 200% for 30 Minutes"
SENDMSG 6 "You have <$HUMAN(Bank)> Million left in your account"
close
#ELSEACT
SENDMSG 6 "You do not have enough funds on your card!"
goto @2times
i like it. If this feature were added, i suppose dropping gold out of your bag when you died would be a good idea. Would encourage bank use 
