I don't think this news is really new, but nobody seems to have posted about this here so far.
When '3' phased out the Flat 12 prepay tariff, there was nothing to replace their Add Ons ( called 'Stretch' ) which were offered with that tariff.
However, 3 have been forced to start offering some of these now, and although they are by no means as good value as those still available for Flat 12 users, they may be of use to some here.
Full details may be viewed at
http://www.three.co.uk/Pay_As_You_Go/Voice_Add_ons The £10 topup -> 3000 texts, 100 mins., and 500 MB internet;
The £15 topup -> 3000 texts, 300 mins, and 500 MB internet;
The £25 topup -> 3000 texts, 500 mins, and 1 GB internet.
In addition to these, 3000 texts can be bought for £5; 300 '3' to '3' minutes for £5; 500 MB internet for £5;
and an internet daily rate, with a FUP of 120 MB, for just 50p. ( This last one actually lasts 2 days, as it ends at midnight on the day after you purchase it. )
All 3 prepay Add Ons ( except the internet daily one of course ) last for 30 days from purchase.
EDIT:-
For comparison purposes, details of the 'Stretch' offers for Flat 12 users can be seen at
http://www.three.co.uk/Pay_As_You_Go/Flat12The £25 will give you 700 minutes, for instance, but doesn't include the generous allowance of texts and internet use.
So perhaps the new Add Ons have more to commend them than I first thought.