This is very true @la7. Everyone has a different definition of value for money. For many people, that may be the lowest payment possible, and fortunately, between virtual networks and resellers, there are a lot of options.
For many others though, value may be more than an arbitrary bottom line, and can include things like the quality of products or services they're receiving.
For example, say I was in the market for a specific model of second hand car. There's a reseller nearby who will buy and sell any car. He has the model I want for £5500. I don't know a lot about cars, so I can't really determine the condition its in. The reseller is offering a 12 month warranty, backed up by a third party.
Further down the road is a licensed garage for the actual manufacturer. They have the same model of used car in stock, same mileage, same condition. They're charging £6000. But it's an approved used car by the manufacturers standards, that comes with a 3 years extended warranty for parts and labour that the garage will take responsibility for itself.
If you know enough about cars to identify one in good condition. If you're confident that you have the time and necessary skills to problem solve, should an issue arise with the car after you buy it. And if you want to keep your costs down as much as possible - then the first option may be something you want to consider.
On the other hand, there are people who may want the extra peace of mind of that comes from the direct sales channel. It may be slightly more expensive, but it inspires more confidence; and should things later go wrong, you know exactly who to turn to, and the quality of support is usually much higher. For them, this may be seen as better value.
One thing you couldn't do though, is argue that the licensed garage charges the same (or less) than the reseller down the road. You may end up with a similar product, but you're not getting the same extras, the same level of support, or the same aftersales care. These things all cost money that someone has to pay for. If you don't think you'll make use of them though, there are other low cost options available.
As for data, those prices seem pretty fair considering O2's other propositions. It may be £10 for a 1GB data bolt on. But a 1GB mobile data SIM also costs £10. And a £10 top up on a Big Bundle PAYG sim only gets you 500MB of data. The best value for money would be to find a tariff that just exceeds your needs, so you wouldn't be reliant on purchasing frequent bolt-ons.
Hope this helps
