Feel free to link to this web page from Facebook, twitter or your blog. If you have some additional information that you think I could add to my guide then get in touch.
I decided to compile this guide as it seems very difficult to get quick and simple answers to questions about O2 PAYG tariffs and Bolt Ons and how you choose them and check the status of them etc. I have compiled all of the information and personal experience of O2 into this simple guide.
Remember its always best to use Wi-Fi where you can as its free and quick but obviously while you are on the move you will need to make use of the 3G data network, this is when having the correct Tariff/Bolt-on is very important.

Do you own an iPhone with a Pay as you go SIM? Perhaps your free unlimited data deal that you got with your new iPhone is about to run out and you are wondering what options are available to you. Hopefully I will have all the answers for you here in my guide to O2 PAYG Tariffs and Bolt ons. By the way when your unlimited data deal runs out you get a text message like this.
"O2: Your unlimited data period's ended. So we've switched you to a £10/month Bolt On with 1GB data, 50 picture messages, and free Wi-Fi. call 2202 for info."

If you own an iPhone or in fact any smartphone on PAYG you will need to use Cellular Data at some point. With an O2 Pay as you go SIM you do NOT get any data allowance included as standard so you must either select a Tariff that gives you some or add a web Bolt on. Tariffs and Bolt Ons are different optional extras that can be added to your O2 pay as you go sim. You can have one or the other or both depending on your needs.

There are several different PAYG tariffs available, which is the best for you?
Well that depends on your circumstances and how you are going to use your phone.

You need to understand that as well as o2 "Tariffs" there are things called "Bolt ons", by combining a tariff and a Bolt on you can get a great deal that suits you.

Know your current o2 Tariff
Want to know what tariff you are currently on? If so this is how to do it :
If you are on o2 PAYG and want to know what tariff you are currently on all you have to do is..
on your iPhone
Tap the Phone icon.
Tap Keypad
Enter 2202
Tap Call and wait while it tells you about various tariffs and deals available from o2.
After about 45 seconds it will tell you your current tariff.

For example I have just rung from my iPhone and it says "Your on o2 Unlimited at the moment".

If you are on the o2 unlimited tariff and you top up £15 or more then you will get a text message like this.
"O2: thanks for topping up. you will now receive one month of unlimited free calls and text messages to other O2 numbers from 1209. Enjoy"

O2 Data Bolt ons
Bolt ons are extras that you can add to your PAYG SIM that will give you things such as 3G data

On o2 PAYG there are three Web Bolt Ons you can choose from:
Name - Monthly Cost - Data - MMS - WiFi*
1) The Basics £3 100MB 0 No
2) The All Rounder £6 500MB 20 Unlimited
3) The Works £10 1GB 50 Unlimited

The Basics Web Bolt On costs £3 a month and you can use up to 100MB of UK data each month. NO
The All Rounder Web Bolt On costs £6 a month and you can use up to 500MB of UK data each month, send 20 picture messages. Plus you have unlimited wi-fi access.
The Works Web Bolt On costs £10 a month and you can use up to 1GB of UK data each month, send 50 picture messages. Plus you have unlimited wi-fi access.
*Note WiFi here means The Cloud's UK Wireless LAN network and the BT Openzone UK Wireless LAN network.

These Web Bolt Ons (The Basics, The All Rounder, The Works) apply to use in the UK only, NOT abroad.
A Bolt On will take up to 48 hours to activate, you will get a text message to confirm when your Bolt On has been activated.
Once activated Bolt Ons will continue to be applied and your monthly payment deducted each month on your anniversary date, until you opt out of the service.
Each month you will receive a reminder text message 48 hours before your monthly Bolt On payment is deducted.
If you wish to opt out you must do so at least 48 hours before your next monthly anniversary date otherwise your monthly Bolt On charge will be deducted from your balance.

Bolt On allowances must be used before your next anniversary date.
Unused allowances cannot be rolled over to subsequent months.

How to get/cancel the web Bolt Ons
To OPT IN to The Basics Web Bolt On send a free text message containing the keyword "BASIC" to 21300 or call free on 2425 from your O2 mobile.
To OPT IN to The All Rounder Web Bolt On send a free text message containing the keyword "ROUND" to 21300 or call free on 2425 from your O2 mobile.
To OPT IN to The Works Web Bolt On send a free text message containing the keyword "WORK" to 21300 or call free on 2425 from your O2 mobile.

To OPT OUT of The Basics Web Bolt On send a free text message containing the keyword "BASICOFF" to 21300 at least 48 hours before the next payment is due or alternatively call free on 2425 from your O2 mobile.
To OPT OUT of The All Rounder Web Bolt On send a free text message containing the keyword "ROUNDOFF" to 21300 at least 48 hours before the next payment is due or alternatively call free on 2425 from your O2 mobile.
To OPT OUT of The Works Web Bolt On send a free text message containing the keyword "WORKOFF" to 21300 at least 48 hours before the next payment is due or alternatively call free on 2425 from your O2 mobile.

Want to know your current o2 Bolt On?
on your iPhone Tap the Phone icon.
Tap Keypad
Enter 4444
Tap Call and wait while it tells you about various tariffs and deals available from o2, select Option 2

The works - £10 a month
If you are on this Bolt and you have at least £10 credit left you will get a text from O2 like this:
"O2: Your WORKSWEB bolt On is now active and £10 payment has been taken from your calltime balance. Your next payment will be taken on 12 Oct"

If you do NOT have enough credit on your phone when the Bolt On is due to be taken you will get a message like this
"O2: Unfortunately you don't have £10 credit for us to activate your WORKSWEB Bolt On. Top-up & we'll try again."

How to find out how much data allowance you have left.
This is very easy to do, simply send a Text message (free) as follows.
Text the word BALANCE to 20202 and you will receive two text messages back instantly. I have just tried it and I got the text message :
"2 of 2: WORKSWEB Bolt On - You have 391.2 MB web and 34 pic msgs left this month. This expires on 12 Oct." The other text message I got was telling me what tariff I was on.

How much 3G data have I used on my iPhone so far?
Did you know that the iPhone has a built in 3G data counter so you can see exactly how much data you have used.
In this example its on an iPhone 3GS with Firmware version 4.2.1
1) From the home screen, click on the Settings icon.
2) Tap the General icon.
3) Tap Usage and scroll down to Cellular Network Data, in this section it shows you how much 3G data has been sent and received (since it was reset).
See my screen grab from my iPhone ----->>
As you can see I have used 260Mb of Network data since I last renewed my bolt-on.

If you have not used this facility before then obviously these values do not mean anything.
What you need to do is next time you receive a "Bolt On activation message", goto this usage section and tap Reset Statistics. This way it will keep track of how much 3G data has been received so you can see if your are getting near the limit of your bolt on or if you could save money by dropping to the "All Rounder" Bolt on.

There are also iPhone Apps available which do the same thing but will also warn you when its running out.
One such app is DataMan Free - Real Time Data Usage Manager. This app even has an auto-reset for your renewal date! This means you won't need to remember to reset the stats when you top up.

Topping up your O2 PAYG phone.
Did you know that you can top up your phone credit using a debit/credit card very quickly, even quicker if you have used the card before. Its worth adding the phone number to your
contacts as "O2 Debit Card TopUp". The phone number is 4444 just follow the guide on how to top up.

o2 top up using same card:

If you have used the card before, call 4444
Then press 1
Then Press 1
Then type in last 4 digits of the card followed by #
Then the 3 digit security code on the signature stripe followed by #
Then the amount in whole pounds you want to top up followed by #
Thats it, simple as that.

This takes less than 50 seconds to top up using this method.

Want to know your credit balance?
Its worth adding this phone number as a contact so you can get quick access to it.
This is the phone number for O2 Balance:

*#10#

On an iPhone it will show your balance on screen. e.g. "Your balance is £9.94."

No credit left and no money to top up, don't worry!
Did you know that O2 PAYG has a service called "Lend us a Quid", this will allow you to borrow £1 credit to make a phone call if you have less than 50p of credit and
don't have any money or a credit card to top up. How to use this service..
Call free 4444

If you use this service then you will get a text message saying..
"O2: thanks for using the O2 Lend us a Quid service. Your loan of £1.00 calltime needs to be repaid by 14/09/11" so don't forget to top-up by then.

I hope you found my O2 PAYG iPhone guide of use, if so feel free to link to this page from Facebook or your blog.

More info on o2 tariffs
All the o2 PAYG Tariffs.

Thanks
Andy