Bear in mind that the tag system enables you to avoid the truly enormous queues you can get in the summertime, and means you don’t need your co-driver to be awake when approaching the tolls.
You do pay €40 for the tag, but that’s a deposit – send it back and they credit it to you. And it works out a little cheaper – you get charged in € converted to £ at commercial rates, rather than the tourist rates you’d have obtained your Euro notes in, or the frankly terrible rate you’ll get if you hand your credit card over.
But mostly it’s about feeling smug as you cruise past the hordes of frustrated drivers stuck in yet another one hour queue……..