Buying an IPhone 5....
Here is a spreadsheet of monthly costs of different network offers....
It shows in most of the offers that the less you pay per month the more you have to pay upfront for the iphone for example.... 
02..
26.00
per month Unlimited Minutes Unlimited Texts   
Phone price

£249.99

 

£46.00
per month

Unlimited Minutes

Unlimited Texts

1GB Inclusive data

Phone price

Free

26.00
per month      Unlimited Minutes  Unlimited Texts
Phone price

£249.99

 

31.00
per month

Unlimited Minutes

Unlimited Texts

1GB Inclusive data

Phone price

£199.99

 

£41.00
per month

Unlimited Minutes

Unlimited Texts

1GB Inclusive data

Phone price

£49.99

 

£46.00
per month

Unlimited Minutes

Unlimited Texts

1GB Inclusive data

Phone price

Free

`

minutes	UK texts	UK internet	Monthly cost	Handset cost
Unlimited	Unlimited	2 GB	£42 a month	£49	Buy iPhone 5
Unlimited	Unlimited	1 GB	£37 a month	£99	Buy iPhone 5
600	Unlimited	500 MB	£33 a month	£149

£104.99Apple iPhone 5 16GB White

+

unlimitedcalls

+

unlimitedtexts

+

1GBdata

=

£36 a month^**

 

244.99Apple iPhone 5 16GB White

+

100minutes

+

125texts

+

250MBdata

=

£25 a month^**

 

£49.99Apple iPhone 5 16GB White

+

unlimitedcalls

+

unlimitedtexts

+

3GBdata

=

£51 a month^**