Is it generally cheaper to buy PAYG sims when you go abroad? We're driving to Italy via France, Switzerland, Belgium,Luxembourg etc and as we're going in 2 cars it would be handy to be able to keep in touch with each other (not that we'll get lost or anything like that-ha).Two of us are on Orange, 2 on Vodafone, 1 on T-mobile, I've been trying to work out who gives the best deal but its so complicated. TIA