I think that is what it could mean, but it is up to you Alaskan....could make a case that you should only have to pay $50 really, and if Mad and I lose (which we won't) we each pay $50.
Pound is about 1.5 dollars at the moment, but on Paypal you can pay in any currency and it automatically converts, so no worries there.
The UK is, I believe, the only full member of the EU who refused to replace their own monetary system with the Euro, which I am grateful for to be honest with the mess that Europe is in with money etc....