I have a dual sim phone - now both sims are with Tesco mobile. I am looking to change mobile service provider for one sim and leave the other SIM with tesco mobile itself. Which is the cheapest pay as you use mobile service provider? I dont want to topup every month. When the credit finishes I prefer to top at that point. Any link to compare the per min mobile phone call charges and per mb mobile data charge? In case the tesco network goes down (which happened several times this year) I could use the other provider. Also I would like to use this when I roam in other EU countries. Any help regarding the best and cheapest alternative to tesco mobile considering value for money and good customer support?