Although you have misunderstood calvin's question,i'd like to correct some of your statement..with maxis prepaid plan,u can view your current balance of both the subscription(internet) and the hotlink prepaid(simcard itself) in the maxis broadband website..The most important thing for maxis prepaid plan is,even your INTERNET subscription expired,there WILL ALWAYS BE a balance of RM1.00 in the SIMCARD..when INTERNET is expired,you can't surf all internet addresses EXCEPT for maxis broadband website(required to surf this site everytime u connect to maxis 3G connection in the iPad,in order to surf the net freely)

In my case,when my ipad SIMCARD only have RM1.00,i top it up using Post-Aid topup from my iphone 4(also maxis) with a minimum of RM10..so,my balance is RM11.00..now,in order to surf the net from my ipad,i need to on the 3G,open safari,go to maxis broadband site, n go to 'buy subscription'..the are lots of option there whether u want;

2 hour pass=RM3=100mb(i think),
1 day pass=RM8=500mb(my favourite if need heavy download)
2 days pass=RM10=500m(i think)
7 days pass(don't know the usage n rate)
etc

So,let say i buy the 2 hours pass,maxis will deduct it from my SIMCARD,with the balance now is RM8..the next time i want to surf the net,i just go to maxis broadband site,n buy subscription again..it's that easy..So far,maxis 3G connection never fails me,n its fast too

Thanks dude..i've been wondering the same thing