1. A prepay mobile – a mobile where you pay for your usage in advance.

2. A prepaid mobile – a mobile where you've paid for your usage.

I'd be more comfortable with #1, as #2 implies that you've already paid for all your future usage.

Sounds like both are same. The first one suggests that I pay in advance. The second one, I've paid for my future usage, which I think means pay in advance too! But someone told me that the first one is equal to postpaid mobile and the second one is equal to pay-as-you-go plan. But I think the first one refers to pay-as-you-go and the second one is equal to post-paid. Which is true?

I ask because I went to vodafone sites and most of them use the first term but it looks like it means for the second term and that makes me confused. Well try these sites :

http://online.vodafone.co.uk/dispatch/Portal/appmanager/vodafone/wrp?_nfpb=true&_pageLabel=Page_B... and http://www.vodafone.co.nz/pricing_plans/prepay_landing.jsp?item=prepay and http://www.vodafone.com.au/rep/redSim/payment.jsp?gs=foryou&hd=mobiles&st=promo280803&ss=redSim_payment - uses the term prepay which i believe prepay means pay-as-you-go

http://www.hotlink.com.my / - uses the term prepaid but is a pay-as-you-go plan (because I use it) Emotion: smilehttp://www.m1.com.sg / - uses the term prepaid and also pay-as-you-go at the same time.

Can someone explain me the right term for pay-as-you-go is it prepay or prepaid? And tell me a more easier explanation for the difference Emotion: stick out tongue
They all mean the same thing. You 'top up' your mobile with more 'credit' when you need to. You buy a certain value of calls in advance as you need to. Pre-pay, pre-paid, pay as you go, all refer to this.

The only other way to pay for mobiles is on 'contract' where you are billed monthly and pay a set amount for a set service.

I'm a bit confused by your concept of paying for all future useage in advance - how could you possibly do that? One payment for the whole of your life? No, doesn't happen.
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Used to ask about this and you posted a comment also Nona and this guy named MrPedantic wrote about the terms. You can refer to http://www.EnglishForward.com/English/PrepayPrepaidMustPrepaid/xzdk/Post.htm

So Nona, was he the cause of my confusion or he was correct but Im the one who is still confused? BTW, is it ok for me to use either usage or useage as I saw you used useage? Emotion: smile
I can't quite follow what he meant either, but in a later post he says

"you could also interpret 'prepaid' in 'prepaid mobile' as meaning 'mobile which uses prepaid top-ups'.

So there seems to be a case for either version!"

so it seems that in the end he agrees that either prepay or prepaid will apply to these phones.