I have a Wifi extender in my van which is great when you have a connection that allows only one device to connect at a time, as you have your own internal network in the van where all your other devices can connect to on the back of that one device connection. The problem comes if you need Email access and there is no Wifi and like me you are too mean to pay for out of country roaming charges. I have just purchased a Freedom Pop Mifi for about £50/- which gives 200MB of free data download per month via 3G and 4G. More than enough for Emails. It is a pocket sized device that has an internal battery which is charged via a USB charger. The coverage is all of UK, most of Europe and they claim to be adding more countries all the time.
When I switched it on I got a 3G connection straight away which is more than my own mobile gets via O2.
I will report how I get on with it on my next European tour. The information can be found here:
Freedom pop link