As a Brit in Hong Kong, on a US dominated internet I sometimes run into currency conversion issues.  XE.com  is my converter of choice.

But then as a Firefox using Brit, in Hong Kong, on a US dominated internet, I figured (see the US influence at work...) that there had to be an extension available to ease my irritation.

It turns out there are several - but I haven't yet tried them as I was sidetracked into making this post.... 

One that seemed to have good reviews is ViewMyCurrency. The developer  has an idiosyncratic choice of domain name.  But at least it's not all false advertising - he has a real recipe for HamsterSoup as well.

The potential for mischief (and psychological scarring) is huge.  As we don't have a hamster, I may just leave it on the screen at home, and claim I was looking for a birthday treat for the cats...