Soon we hope to visit some friends of ours who have moved to Cumbria.When we go I would like to take my laptop with me but where they live there is no Broadband and so they have to use a "dongle"(???).Would I be able to use this and does it cost them money if I did ?
well if they can use it then yes, you could plug it into your laptop and use it!
You can't both use it at the same time though (well not easily!) and it will either cost them when you use it or at least count as part of the download allowance they have paid for!