Switch from monthly to PAYG - calls outside allowance?

[Anonymous]

I am planning to change from monthly to PAYG in May 13.  At present, calls to the Isle of Man (01624/07624) are included in my tariff. They no longer will be, so my £10 per month PAYG will be for 75 mins UK calls, 500 texts and 100MB internet only. I can't quite get my head around how the £10 per month will be allocated. Does the £10 get taken out straight away, so your account balance is nil and you carry on through the month until you reach your limit on the UK calls/texts/internet? Then you obviously would have to top up or wait until the next month start date.

But here's my blind spot! If that's the case, how are any calls, texts etc outside your allowance then debited? They can't be taken off a nil balance. Or am I being very stupd?!

Thanks

[MI5]

Some PAYG SIM's require you to apply a top up to "buy" an allowance. Then your balance is zero and you would have to top up more to gain a positive balance to make calls outside of your allowance. Some other SIM's give you a "Free" allowance when you top up so you keep your credit for calls outside of your allowance. You need to choose the deal that best suits you.

[Anonymous]

Thanks.  I am thinking of the PAYGoGo - the deal that doubles your allowance. 

O2 says: Here are the top-up values you can choose from each month. If you want to use more minutes, texts and data than your monthly allowance, feel free and we’ll simply charge you at the standard O2 rate.

I am still confused! How do they charge you for extras if your £10 is soley to cover the UK calls texts and internet?  Do you have to top up again in that month? 

[adamtemp64 · Accepted solution]

£10 gets you the payg go go deal then you top up for calls outside the 75 mins or for international calls

[Anonymous]

Thanks that's a very clear and speedy reply!