Tesco Mobile have launched a new tariff, called Pay as you go Lite, aimed at low users who are attracted to Asda as they don't top-up monthly. See
here.
Superficially it looks the same as Asda, with call charges of 8p / min. and texts for 4p each. However, when you look at
all charges in detail, you see that it is not the same thing at all. Whereas Asda charge just 20p per MB for data, Tesco Lite charge a stonking £4 per MB - a whole 20 times more!
There are free SIMs on offer at the Tesco website, but
avoid if you plan to use your SIM for WAP. There are far better offers out there for data users!